High-pressure (aka "true") aeroponics - nutrient schedule?

QuentinQuark

Well-Known Member
Hey all,

So a quick intro, I have a DWC system in a spare bedroom using 12 storage totes, 2x1000w HPS, cooltubes, Adjust-A-Wings, etc.

For my next set up, I would like something that is less maintenance. The problem with DWC is you have to use a buttload of nutes, a buttload of water, a buttload of H2O2, drain and fill a buttload of tubs every week or two, and constantly monitor pH on a buttload of tubs. Not to mention that if you have heat issues, you have to worry about cooling a buttload of tubs instead of just one - if I wanted to use res coolers I would need 12 of them!!

After doing a lot of thinking and researching, I have decided I am going to go the "true" aeroponics route. Misting nozzles with 50-micron droplet size, high-pressure (i.e. 100psi) pump, and a single external reservoir. The table will be 5'x6', house 120 sites (4 sites per sq ft), and have 30 nozzles at the bottom. Reservoir will be 20 gallon storage tub with chiller and air pump and stones to maximize DO.

I am working on which nozzles, which pumps etc, if anyone wants details let me know.

But one thing I can't seem to find good info on is nutrients and feeding schedule. From my reading, there appears to be a problem around week 5 where the plants go a little berserk, but then again the threads are mostly by this guy Pod Racer who seems like a bit of a nut job. He talks about the plants dumping back a bunch of Nitrogen at that time, and over the course of 12 hours your ppm's climbing way up and your pH dropping way low and if you don't catch it you're hooped.

So anyways, is anyone running this type of set up, if so what is your feeding schedule, and if not can anyone point me to some good info on this? Obviously this info is cannabis-specific, so a lot of the sites like BioControls don't have the detail I am looking for.

I am always up for some trial and error, but if anyone has already made the mistakes ahead of me, the info would be appreciated!

Thanks!
 

FilthyFletch

Mr I Can Do That For Half
Ive posted many aero grows and how to build tuts on here. a 20 gallon res wont be big enough for this setup look at a 50 gallon res this will help ensure the pump never runs dry on it. Not sure who the gy you are talking about but seems to be way off on what you stated his beliefs are. Aero is pretty simple and as long as the grow has some hydro expirence straight forward. I have found running the pump will give better results then cycling it on and off tried both over last 5 or so years and always on works best and is easier on the pumps. The misters and high pressure lines will be the bulk of your cost considering true 50 micron heads will cost around $12-$30 each if you use the correct ones and the presure line about $7 a foot. You ll be looking at a few thousand gph type pump so few hundred bucks there.The nute schedule can not be generalized like your asking as every nute make has a differnt feed schedule and different ppm at set points. Fox Farm is a great aero nute little ph flux per week and stay on the chart schedule and your good and once your used to it it can be pushed to a higher max.I suspect with the amount of sites your trying to cram in you want no veg time and will use clones and go for small plants with quarter or so yield per plant. I prefer to run 32 plant setup with no less then 1 foot between netpots and then side by side I like 18 inch spaceing as I prefer aero rails with extra NFT run off as a secondary feed.I like to veg clones 10 day til about 8-10m inches tall then flower 5-6 weeks then harvest usualy yield is about 2-3 lbs dry in this type of setup with 2 600 watt lights on a tandem light mover. Keep ph at 5.5 for best results never about 5.8 max. i have never needed a chiller for any grow but res temsp should be around 68F maxno colder then 65 F to avoid shock to roots. Change your res every week .The guy saying big nitrogen dumps or week 5 beserk makes no sense as around week 5 -6 flower your flushing and done in a correct aero grow unit assuming growing a good indica and not some sativa. Pretty basic follw the feeding chart from the nute maker. keep ph at 5.5 and res around 68 and misters on 24-7 and your good
 

Atomizer

Well-Known Member
I have a aero system in the building stages too but its vertical not flat. It uses a 12gph pump with 24 nozzles running at 60-95psi. The only advice i can offer is not to rely solely on the pump to provide the mist, pump failure is the bane of TAG :wink:
 

QuentinQuark

Well-Known Member
Ive posted many aero grows and how to build tuts on here. a 20 gallon res wont be big enough for this setup look at a 50 gallon res this will help ensure the pump never runs dry on it.
The pumps that I am looking at are diaphragm pumps, they don't get damaged if they run dry. They are high-pressure low-flow pumps made for misting systems, agricultural spraying, etc.

Not sure who the gy you are talking about but seems to be way off on what you stated his beliefs are.
That doesn't surprise me, he was pretty "out there".

Aero is pretty simple and as long as the grow has some hydro expirence straight forward.
Now THAT does surprise me. From what I have read, true high-pressure, tiny droplet aeroponics is not for the faint of heart.

I have found running the pump will give better results then cycling it on and off tried both over last 5 or so years and always on works best and is easier on the pumps.
So you don't do 30 secs on / 3 mins off?

The misters and high pressure lines will be the bulk of your cost considering true 50 micron heads will cost around $12-$30 each if you use the correct ones
I was planning on using a plastic misting nozzle with a 55-micron droplet size, I have seen the exact same ones on several websites, for around $1.50 - $2 each. I have also seen brass nozzles with an even smaller average droplet size, for around $4 - $5 each.

and the presure line about $7 a foot.
Yikes! I was just gonna use 1/2" schedule 40 PVC! Will that not work?

You ll be looking at a few thousand gph type pump so few hundred bucks there.
I was planning on using what is known as a "diaphragm pump", which is a true low-flow (like 1 Gallon per minute!) high pressure (100psi) pump. But yes it will cost a couple hundred bucks...

The nute schedule can not be generalized like your asking as every nute make has a differnt feed schedule and different ppm at set points.
That makes sense. I guess what I was looking for was some advice like "keep a close eye on the plants in week 5, and if/when they start to look like they're developing a K burn, that's actually a calcium deficiency because the N is dropping the pH out of the range where calcium can be utilized", or "you will need a res size of xyz liters per plant assuming zero-veg SoG", or "be careful and make sure you ALWAYS top up your nute tank with water or the ppms will climb too high and they will burn", or " be careful to NEVER top up your tank with water or the boogeyman will get you", just some general advice on how to feed in this system, as it will clearly be much less forgiving than DWC (which is in itself not very forgiving!).

Fox Farm is a great aero nute little ph flux per week and stay on the chart schedule and your good and once your used to it it can be pushed to a higher max.
Cool, good to know! Never played around with FF before. So your saying to stick to the chart? Usually people recommend to not go anywhere close to the dosage recommended on the label because it will cause fert burn. So do you think one should use higher concentrations of nutes in an aero grow vs. DWC because there is a much higher ratio of plant to nute? Or would you also recommend following the label strength in other hydro setups?

I suspect with the amount of sites your trying to cram in you want no veg time and will use clones and go for small plants
You guessed it! ;)

with quarter or so yield per plant.
Well, i'm hoping for more than that... Al B Fuct was pulling 40g (1.5z) per plant in zero-veg SoG ebb'n'flow, I would love to hit that mark!

I prefer to run 32 plant setup with no less then 1 foot between netpots and then side by side I like 18 inch spaceing as I prefer aero rails with extra NFT run off as a secondary feed.
So you use high pressure, low flow, but you run them 24x7 and let them soak the roots? I thought the point of true aeroponics was to basically let the roots breathe in air, and just give them nutes/water via an aerosol mist? And the roots don't even grow thick taps down to the bottom, they kind of "puffball" with tremendous lateral (fishbone) growth?

I like to veg clones 10 day til about 8-10m inches tall
I actually would like to do this, but do you think that 4 plants per square foot would not be anough space for this? I would trim everything on the bottom 1/3 to 1/2 of the plant, basically just grow the top cola and maybe 1 or two secondary buds, so there should be plenty of airflow...

then flower 5-6 weeks then harvest
Holy, that's a short flowering time! What strain do you use? I didn't think you could do much less than 9 weeks.

usualy yield is about 2-3 lbs dry in this type of setup with 2 600 watt lights on a tandem light mover.
Nice, that's good numbers for 10 days veg + 5-6 weeks flower. How many square feet total? What kind of reflector? Are you enclosing the growing area in reflective material? What are you doing for air circulation?

Keep ph at 5.5 for best results never about 5.8 max.
Yes, I usually aim for 5.8 as specified on the chart in the first post here

i have never needed a chiller for any grow but res temsp should be around 68F maxno colder then 65 F to avoid shock to roots.
Right, in my current DWC room, even with the lights cooltubed the temps were still getting too high and the water was getting too warm, so I had to resort to putting a big ass A/C in there to get the water temps down by getting the whole room temps down. A res cooler would have been much cheaper and simpler, but with 12 tubs it wasn't possible.

Change your res every week .
Right, in my DWC grow I have been changing the res every two weeks (following Al B Fuct) but in the new aero grow I was definitely going to do weekly dumps AT LEAST.

The guy saying big nitrogen dumps or week 5 beserk makes no sense
Yes, it didn't make sense to me either that the plants would suddenly dump a bunch of stored up N back out. Firstly, i'm sure the plants have some nutrient storage capacity, but if they could store that much N then we wouldn't ever see cases of fert burn! I think the plants use what they can, store a little, and if there's more than that, they get burnt. Secondly, I know there is a point a few weeks in to flowering where a plant "transitions" from vegging mode to flowering mode, stops stretching and throwing out new shoots, and starts to really kick in to flowering gear, but I thought this was more like at the end of week 3.

as around week 5 -6 flower your flushing and done in a correct aero grow unit assuming growing a good indica and not some sativa.
See now that is where you lose me. I have never heard of that short of a flowering time, and I stick to pure indica strains.

Pretty basic follw the feeding chart from the nute maker. keep ph at 5.5 and res around 68 and misters on 24-7 and your good
Thanks for the feedback bro!
 

QuentinQuark

Well-Known Member
I have a aero system in the building stages too but its vertical not flat. It uses a 12gph pump with 24 nozzles running at 60-95psi.
Would you happen to have the make and model of that pump, and the nozzles?

The only advice i can offer is not to rely solely on the pump to provide the mist, pump failure is the bane of TAG :wink:
Awesome advice! I was actually thinking of setting up redundant pumps, two pumps misting the table, with two separate misting systems, alternating the nozzles between the two. That way if a pump dies, the other one is still running and still providing some mist to the system.

The problem with this idea, is that so far I can't even find a pump that will run 30 nozzles! If I were to go with two redundant pumps, each pump would have to run 15 nozzles, and that is more pressure than the pumps can handle. 30 nozzles is 2L/min, 15 nozzles is only 1L/min. If you look at the flow/pressure charts for most of the pumps, they hit cut-off pressure at flows much higher than 2L/min. I am talking to Aquatec, Flojet, and Shurflo, to find a suitable pump.

Which reminds me, does anyone know and can explain the difference between a demand and a bypass pump?
 

Atomizer

Well-Known Member
Hi Quentin,
I see you`ve done the research, it can be a minefield to figure which way to go :wink:

A demand pump has a pressure switch incorporated into it whch turns the pump on and off, normally the range is 15-20psi. For example, the pump cuts in when the pressure drops to 40psi and cuts back out again at 60psi.

A bypass pump will build pressure until it reaches its bypass limit, the water flow then runs in a closed loop inside the pump head to prevent over pressure damage.

Droplet size is related to water pressure, so ideally you want instant constant pressure from the get go..a pump builds up pressure when its running and loses pressure when you turn it off, its not instant or constant.
You`ve no doubts noticed that Biocontrols use 3-5 second misting pulses with their overpriced cycle timers. A pump cant respond that fast so you`ll be forced into using a longer misting duration to reach the pressure and still be generating larger droplets at the beginning and end of each misting cycle due to the lower pressure.
Nozzle output is also related to pressure, higher psi= higher flowrate through the nozzle. Pumps work the opposite way, higher pressure = lower flowrate.. minefield :wink:

I designed my system to take the pump flowrate out of the equation as much as possible. My nozzles deliver 0.14LPM at 72psi. A 3 second pulse using 24 nozzles equates to 170ml per cycle.. so logic says i need a pump that delivers at least 3.4LPM at 72psi?
My aquatec pump delivers less than 0.5LPM at 72psi, but still provides instant pressure. It runs for 8.5minutes once an hour, almost silent running with very low power consumption. It should have a reasonable life expectancy too as it doesnt cycle on/off 500 times a day. The math says it should be capable of running upto 80 nozzles but it`d have to work a lot harder.

The large vertical garden in the making has a 200ft3 (5664L) root chamber. The 24 nozzles will fill it in 3 seconds as it uses gravity to help distribute the mist. A flat garden would probably need more nozzles to get even coverage of the roots.
 

FilthyFletch

Mr I Can Do That For Half
Lets see if I can get responses to what you asked back...

About the simplicity of aero. You will have probably one inline israli filter on this type of setup and then I reccomend another bag filter if its a submersible type pump not need if its an extenal pump. I never really had issues with clogs other then once when I was trying an expirement that went wrong. I always reccomend liquid nutes no powders for aero. any additives that are powder disolve them first before adding.

Misting times... No I do not cycle my pumps at all I have tried many different misting times and have every time found that running my mistres 24 hours on gives me many more benefits. I get larger yields, no clogs as the misters dont have time to dry and cake,less hard starts on the pump from constant restarting, and less chances of a hard pump start tripping s breaker in the grow room.

Im not sure of the nozzels you mean. I have seen the brass kind at like home depot but they were like $4.00 each. I was thinking you were going to use true agricultural grade misters and lines similar to the kind you see in the vegable section at stores that mist the fresh veggies. Those are exspensive and require a high pressure steel line thats about 1/8 diameter and the psi is closer to 200 psi. Have any links to the type of misters you were looking at? I run a lower pressure type setup using the smaller red aero clone misters. These are the ones used in almost all hydro store systems as they are much easier to maintain works just as well for smaller non commercial grows and are cheap if an issue and can be used right inline with 1/2 inch pvc. For aero Im running a 100% pure indica plant. its a clone only passed through just afew people. Its an original clone taken from the pure indica mother used back in the early 90's to create the original Bubble gum strain. Its a short fast flowering plant. With correct setup and co2 I can ahrvest at 5 weeks with 70% red hairs maybe 6 weeks with a flush. i have let it go 8 before but looses quality in relation to growing it aero. Flood I harvest at week 7. On the nutes Fox Farm has always been forgiving for me I never evr burned any plants and I actually now go over the charts suggeste ppms and have learned I can at max get ppms of up to 1900. Its pretty much my nute mainstay although I do want to try a round of Humbodlt Countis complete nute line now that its out. i love thier additives like bushmaster,Purple Max and Gravity.

You asked about the pumps being on 24/7 and aeration. My roots hang down in my chambers and get the mist feed then the longer part of the roots as they get 4-5 feet long sit in the nutrients flowing by constantly so it have a good air flow in the solution as the misters aerated it and then its constantly moving so the roots in the air get O2 and the roots in the solution take whatever nutes they didnt get from the mist. Works great for me for years.

Lets take like my 32 site setup. its a post type design. 4 posts 8 per post on 8 foot long posts basically. it breaks down to about 10 inches between netpots then I have a 18 inch space between the posts and like this the entire area fills up and my plants finish at about 3 feet tall. I do a medium lollipop to th lower stuff and try for maybe a dozen or so colas per plant. In the room I took a standard light mover built a custom 6 foot aluminum cross bar and hong 1 light on each end using a basic adjustable open wing reflector. I can move these up and down via chains and bend the reflector for light angles. The 8 foot track moves both lights back and forth over the setup at whatever speed I set the motor too. i have 2 600 watt digital lights in there and then I run co2 tanks closed room with timed air exchange via auto dampers. i run 3 windo box fans 24 hours a day and then 2 tilt fans under the setup blowing the co2 that fell to the floor back up recirculating it in the room. The box fans I have one about top of the plants I adjust as tey grow.One at the base under them moving the lower air past the stalks and a 3rd at mid plant levael blowing the branches. I keep a 65 gallon res in the room with the submersiable 500 gph pump in it running 24/7. I lost 1 pump in 6 years but was my fault as I left too long and didnt setup a a float valve to an external tank to top the res and it got to low and the pump ran dry and locked. I learned though gone more then a couple days set your backup water supply.

Res change I have found you can go 2 weeks but my ppm drops so i know my plants dont get full feedings so i like to keep them maxed so i change once a week and 5.8 is good but I personally think 5.5 shows a better nutrient uptake when i watch the plants reactions over the years. My rs in the rooms dont get hot stay about 68 ishs on thier own and I have had to add a fish tank heater before to get them up in cooler months.


Now I havent heard his nute dump thing before or seen this. You do get your stretch in around week 3-ish unless you use like Bushmaster which i have found is excellent to stop up growth and make out growth. I find it has plants in flower grow maybe 2-3 inches more then stops and they grow outwards and branch. Luv that stuff. The air temps can manage it too. Without co2 I like rooms around 70-75 and with co2 80-85 ish..

The finish in 5-6 weeks isnt the norm ill grant you that but the strain i use and have dialed in is consistant and yiuelds are about the same each time few dry lbs on a 32 plant setup. I know other strains I have grown tend to finish about 2 weeks early compared to standard dro and about 3 weeks faster to 4 weeks then in soil grows.Like a soil plant stated to finish in 12 weeks will be about 9 in aero and veg time is 50% faster.

Each setup will vary and the same with the growers expirence. Pick your setup go with it watch and keep records and then adjust until you find its max then yoiu will have the best results. Not all aero grows will yield the same or respond the same. the things I stated are what i personally have learned over the yers of growing aero and you will learn along the way your own prefernces and tweaks. Good grows and welcome to aero..you ll never go back
 

QuentinQuark

Well-Known Member
Hi Quentin,
I see you`ve done the research, it can be a minefield to figure which way to go :wink:
Yes, I'm a bit anal that way, and I have learned a TON along this loooong journey!

A demand pump has a pressure switch incorporated into it whch turns the pump on and off, normally the range is 15-20psi. For example, the pump cuts in when the pressure drops to 40psi and cuts back out again at 60psi.

A bypass pump will build pressure until it reaches its bypass limit, the water flow then runs in a closed loop inside the pump head to prevent over pressure damage.
The tech support guy from ShurFlo said "A demand pump shuts off when pressure builds against a closed outlet. The bypass pump needs to be manually shut off."

The tech support guy from Cloudtops said "An on demand pump has a preset high and low operating pressure. It can sense how much pressure is on the outlet side of the pump. So if the pressure is too high the pump will shut off, and if the pressure is too low it will turn back on."

If I read these correctly, then the cloudtops guy said what the shurflo guy said, plus an extra bit of info. The demand pumps can sense when to turn on (when the outlet pressure drops below a certain point) and the can sense when to turn off (when the outlet pressure climbs above a certain point).

I guess that means that bypass pumps don't turn themselves on/off? So what happens to a bypass pump if you try to run a flow too low, won't it get smoked because there will be too much pressure? NO! Because it's a BYPASS pump, meaning that it will somehow "blow-off" the extra flow in order to lower the pressure to within operating range! Have I got that right? And what you're saying Atomizer is that this extra water just gets routed around inside the pump?

Then wouldn't a bypass pump be exactly, perfectly what I'm looking for? No accumulator tanks, no solenoid valves. Use anti-drip nozzles, which will "close" when pressure drops below a certain point. The pressure drop will only happen when the pump gets turned off, and the anti-drip "closing" will maintain most of the pressure in the line. A check valve upstream from the pump will prevent water from flowing backwards when the pump gets turned off, just as the anti-drip nozzles will prevent water from flowing forwards when the pump gets turned off.

So when the pump turns on, it does it's thing, the anti-drip nozzles open up, and you get 30 seconds of high pressure mist, without having to take a lot of time to build up pressure in the line.

Make sense?

Droplet size is related to water pressure
I am looking at the Superfine Misting Nozzles here. According to a guy named Vann in tech support at DripWorksUSA: "The nozzles are rated at 55 micron from 40 -250 PSI". Now that struck me as odd too, because when I was looking at brass nozzles, the higher the pressure the smaller the droplet size. But I did read on one of Pod Racer's threads that there are different types of nozzles (I remember one type was called "Impact" and one type was called "Vortex") and that one of the types has the same droplet size regardless of pressure. I can't find where I read that though. But it would be good to confirm I guess. I'll do that, and if I get an answer I'll post it here. I just sent three emails to different companies to ask about droplet size for these nozzles, just in case Vann was BSing me.

, so ideally you want instant constant pressure from the get go..a pump builds up pressure when its running and loses pressure when you turn it off, its not instant or constant.
Right, so my idea is to use the combination of check valve upstream from the pump and anti-drip nozzles downstream from the pump, to keep the pressure in the line high, let's say 80psi, so when the pump fires up it only has to go from 80psi to 100psi, it doesn't have to go all the way from 0psi to 100psi. What are your thoughts on this?

You`ve no doubts noticed that Biocontrols use 3-5 second misting pulses with their overpriced cycle timers.
I didn't actually! I took one look at the prices of their nozzles and went elsewhere lol. Why would they use such short misting cycles? I thought 30sec on 3 min off was ideal?

A pump cant respond that fast so you`ll be forced into using a longer misting duration to reach the pressure and still be generating larger droplets at the beginning and end of each misting cycle due to the lower pressure.
I hope that my idea of using anti-drip nozzles downstream and a check valve upstream minimizes the pressure loss when the pump shuts off, thereby minimizing the time it will take the pump to reach desired pressure from when it turns on, but I would love to hear some thoughts on whether that will work or not.

Nozzle output is also related to pressure, higher psi= higher flowrate through the nozzle. Pumps work the opposite way, higher pressure = lower flowrate.. minefield :wink:
Righto. Now here is a cool resource that explains how to "match" your pump needs to your application needs. The second graph in Section 3 says that you plot your pump performance chart on a graph with your nozzle performance chart, and the point at which they intersect is the pressure at which your system will operate. So basically you layer your nozzle chart over a bunch of different pump charts until you find an operating pressure you like, and that's the pump you buy. Sweet, right?

I designed my system to take the pump flowrate out of the equation as much as possible.
Using the above "matching" technique this is no longer necessary, although it's too late for you I guess :cry:

My nozzles deliver 0.14LPM at 72psi.
That sounds really high! The ones I am looking at are like 0.055LPM at 72psi!

A 3 second pulse using 24 nozzles equates to 170ml per cycle..
0.14LPM / 60 = .002333LPS * 24 = .056LPS for all 24 of them, * 3 seconds = 170ml per cycle, got it.

so logic says i need a pump that delivers at least 3.4LPM at 72psi?
0.056LPS * 60 = 3.4LPM, yuppers.

My aquatec pump delivers less than 0.5LPM at 72psi,
You lost me. If you know your exact flow requirements at a particular pressure, why didn't you just go with a pump that put out that flow at that pressure?

but still provides instant pressure
Lost me again. How do you get it to provide instant pressure?

It runs for 8.5minutes once an hour,
How did you arrive at that cycle? That's way different than the usual recommendation of 30secs on 3 mins off! Was that through experimentation, trial and error? Was it a limitation of your timer, I know you need a special cycle timer to do 30secs in 3 mins off...

almost silent running with very low power consumption. It should have a reasonable life expectancy too as it doesnt cycle on/off 500 times a day.
Awesome! Can't complain about that! I will definitely have the on/off power cycling, 20 x per hour (every three minutes), although I understand you can water a lot less at night.

The math says it should be capable of running upto 80 nozzles but it`d have to work a lot harder.
If (as you said above) on a 0.5LPM load it can only push 72psi, then expanding to 80 nozzles would give you a higher flow, which would lead to even LESS pressure, probably a LOT less, wouldn't it?

The large vertical garden in the making has a 200ft3 (5664L) root chamber. The 24 nozzles will fill it in 3 seconds as it uses gravity to help distribute the mist. A flat garden would probably need more nozzles to get even coverage of the roots.
Sounds pretty sweet. I'm doing a flat garden, but I did think about going vertical. My thoughts on vertical are, if I were to do it, I would want a system where the plants surround the light, like one of those giants cylinder dealies. But I can never wrap my head around how I would access the plants to check them for health, to trim them, etc. It would have to open up somehow... seems very complicated. I came across something called the cacoon system, but couldn't find out any information on it, it was kind of wierd...

What about feeding/nutes schedule? Just stick to what I know from DWC? Or is it totally different with True Aero? I already decided I will definitely change the res every week instead of every two weeks. But is there anything else? Or just stick to the label like Fletch suggests?
 

QuentinQuark

Well-Known Member
Lets see if I can get responses to what you asked back...

About the simplicity of aero. You will have probably one inline israli filter on this type of setup
That's the plan, it's called a 200 filter. The nozzles I am planning on using actually can come with individual filters, but I am going to get them without, because I will be using one filter on the entire system.

and then I reccomend another bag filter if its a submersible type pump not need if its an extenal pump.
It's an external pump, so no need for a bag filter.

I always reccomend liquid nutes no powders for aero. any additives that are powder disolve them first before adding.
Good advice!

Misting times... No I do not cycle my pumps at all I have tried many different misting times and have every time found that running my mistres 24 hours on gives me many more benefits.

I get larger yields,
I was led to believe just the opposite, that if you keep your misters on 24 x 7 you are soaking the roots and thus not maximizing their lateral growth, they will grow long taproots and not puff out or fishbone as much.

no clogs as the misters dont have time to dry and cake,
Good point. How quickly do things start to cake? I am going to try to keep my "pod" temps at 68F, so I am hoping that a 3 minute off cycle won't cause caking. I don't want to have to go messing around inside the pod every day checking for clogs, I was thinking at most I would have a second full set of nozzles, and would just swap them out at the end of every grow, clean the old dirty set (soak them for a few days) without any downtime on the system.

less hard starts on the pump from constant restarting, and less chances of a hard pump start tripping s breaker in the grow room.
Also good points lol. If this happens I may be out of luck.

Im not sure of the nozzels you mean. I have seen the brass kind at like home depot but they were like $4.00 each. I was thinking you were going to use true agricultural grade misters and lines similar to the kind you see in the vegable section at stores that mist the fresh veggies. Those are exspensive and require a high pressure steel line thats about 1/8 diameter and the psi is closer to 200 psi. Have any links to the type of misters you were looking at?
These are the nozzles I had in mind, look for Superfine Misting Nozzles about 3/4 of the way down the page. Very low flow, very fine droplet size.

I run a lower pressure type setup using the smaller red aero clone misters. These are the ones used in almost all hydro store systems as they are much easier to maintain works just as well for smaller non commercial grows and are cheap if an issue and can be used right inline with 1/2 inch pvc.
That's where the distinction is between "true" aeroponics vs. "pseudo" aeroponics which is really closer to NFT. It is still an awesome and effective way to grow, I have seen some root pics from that style that gave me wood.

For aero Im running a 100% pure indica plant. its a clone only passed through just afew people. Its an original clone taken from the pure indica mother used back in the early 90's to create the original Bubble gum strain.
That's pretty fricking sweet Fletch! Hook a brother up!

Its a short fast flowering plant. With correct setup and co2 I can ahrvest at 5 weeks with 70% red hairs maybe 6 weeks with a flush. i have let it go 8 before but looses quality in relation to growing it aero. Flood I harvest at week 7.
Like I said, I have never heard of that short of a flowering time, but it sounds like you got your system down TIGHT bro!

On the nutes Fox Farm has always been forgiving for me I never evr burned any plants and I actually now go over the charts suggeste ppms and have learned I can at max get ppms of up to 1900. Its pretty much my nute mainstay although I do want to try a round of Humbodlt Countis complete nute line now that its out. i love thier additives like bushmaster,Purple Max and Gravity.
Thanks for the tips, I will definitely check it out!

You asked about the pumps being on 24/7 and aeration. My roots hang down in my chambers and get the mist feed then the longer part of the roots as they get 4-5 feet long sit in the nutrients flowing by constantly
Right, so that's what I meant above by "pseudo" aero which is really closer to NFT. You must have some purdy roots, got any pics?

so it have a good air flow in the solution as the misters aerated it and then its constantly moving so the roots in the air get O2
Ok, now this thread was supposed to be about aero nutrient advice, and it's gone WAY off topic, but this is excellent information so let's see where it goes.

Regarding getting fresh air, or specifically O2, to the roots. In DWC, the grower is constantly bubbling fresh O2-containing air into the bucket, so the roots always have a fresh supply of O2, and there is always lots of O2 getting dissolved into the water (assuming you have your temps under control ;) ). But in aero, where is the fresh O2-containing air coming from? Fletch, you said the misters aerate the roots, but do they? The misters are being fed by a pump, and that pump is pumping water from your reservoir, it's not mixing in any air (although there are some pretty kick-ass systems out there that do this, if anyone wants details let me know) so assuming the root zone is sealed up pretty tight, there's no fresh air getting in is there?

I was thinking about this, and my solution was going to be to add air pump and air stones to the reservoir, even though there's no plants sitting in there like there would be in DWC. My thought process is that this would increase the DO in the water/nutes, which gets pumped to the roots, thus giving fresh O2 just like in DWC? And to supercharge this, I would like to use a res chiller to increase the DO capacity of the water. And to supercharge this even further, I would like to use a medical device called an Oxygen Concentrator to feed the air to the air pumps, but that is an expensive little piece of equipment. Maybe someday...

So anyways how does the rootzone get fresh air in aero? Does everyone use aerate their nutes, and my brilliant idea wasn't all that brilliant? :)

and the roots in the solution take whatever nutes they didnt get from the mist. Works great for me for years.
Ya it sure does judging from your yield numbers!

Lets take like my 32 site setup. its a post type design. 4 posts 8 per post on 8 foot long posts basically. it breaks down to about 10 inches between netpots then I have a 18 inch space between the posts and like this the entire area fills up and my plants finish at about 3 feet tall. I do a medium lollipop to th lower stuff and try for maybe a dozen or so colas per plant.
Ahh, so you're not doing SoG. Right now in DWC I end up with between 3 and 6 buds per plant, and I just pack the plants in nice and tight and trim the hell out of the lower half. Around here, bigger buds are a sign of quality and therefore they bring a better price, so I would rather have more plants and fewer, larger buds per plant. Also I think you can get away with less veg time this way, although you did mention that you only veg for like 10 days.

In the room I took a standard light mover built a custom 6 foot aluminum cross bar and hong 1 light on each end using a basic adjustable open wing reflector. I can move these up and down via chains and bend the reflector for light angles. The 8 foot track moves both lights back and forth over the setup at whatever speed I set the motor too. i have 2 600 watt digital lights in there and then I run co2 tanks closed room with timed air exchange via auto dampers. i run 3 windo box fans 24 hours a day and then 2 tilt fans under the setup blowing the co2 that fell to the floor back up recirculating it in the room. The box fans I have one about top of the plants I adjust as tey grow.One at the base under them moving the lower air past the stalks and a 3rd at mid plant levael blowing the branches. I keep a 65 gallon res in the room with the submersiable 500 gph pump in it running 24/7. I lost 1 pump in 6 years but was my fault as I left too long and didnt setup a a float valve to an external tank to top the res and it got to low and the pump ran dry and locked. I learned though gone more then a couple days set your backup water supply.
I need to look into the float valve thing. It's not such a big deal when I have 5L per plant as I do in my current DWC. But when I move to a single res for that many plants, they are gonna be thirsty, and i'm gonna have to keep that tank topped up or else!

So how exactly do you set this up. I mean I know basically what a float vale is, but as far as details, so do you have a second res filled with plain water with a pump in it, and the float valve triggers the pump on and off to keep the nute res topped off? Or is it some kind of passive gravity fed system, you keep your backup water tank up higher than the nute tank, and the float valve just opens and closes the water line?

Res change I have found you can go 2 weeks but my ppm drops so i know my plants dont get full feedings so i like to keep them maxed so i change once a week
So they can go for a full two weeks on a single tank without showing any signs of deficiency? That's what i'm wondering, again taking a page from the Al B Fuct book, he says that you want to run your plants with as few nutes as possible without showing any visible signs of nute deficiency, and that way you don't have to flush. The other school of thought is StinkBud style, crank them as hard as they can go without showing any signs of burning, and then flush the hell out of them. There are arguments for both I guess. According to ABF, doing it his way you get the plants still putting on weight in the last couple of weeks before harvest, and supposedly this is the time they pack on the most weight. If you're flushing during that time, the plants aren't putting on any more weight.

and 5.8 is good but I personally think 5.5 shows a better nutrient uptake when i watch the plants reactions over the years.
I hope I get to the stage where I can spot the optimum pH for my setup and strain, very cool. I haven't been running my DWC grow for long enough.

My rs in the rooms dont get hot stay about 68 ishs on thier own and I have had to add a fish tank heater before to get them up in cooler months.
Well it sounds like you live in a cold place, I certainly don't envy that, but it must be nice not to have to worry about nute temps!

Now I havent heard his nute dump thing before or seen this. You do get your stretch in around week 3-ish unless you use like Bushmaster which i have found is excellent to stop up growth and make out growth. I find it has plants in flower grow maybe 2-3 inches more then stops and they grow outwards and branch. Luv that stuff. The air temps can manage it too. Without co2 I like rooms around 70-75 and with co2 80-85 ish..
Your room temps get up that high, your res tank is in your room , and somehow your res tank doesn't get that hot? What am I missing?

The finish in 5-6 weeks isnt the norm ill grant you that but the strain i use and have dialed in is consistant
As I said, can't wait till I'm there!

and yiuelds are about the same each time few dry lbs on a 32 plant setup. I know other strains I have grown tend to finish about 2 weeks early compared to standard dro and about 3 weeks faster to 4 weeks then in soil grows.Like a soil plant stated to finish in 12 weeks will be about 9 in aero and veg time is 50% faster.
Yes, I have noticed that hydro cuts flowering time nicely :)

Each setup will vary and the same with the growers expirence. Pick your setup go with it watch and keep records and then adjust until you find its max then yoiu will have the best results. Not all aero grows will yield the same or respond the same. the things I stated are what i personally have learned over the yers of growing aero and you will learn along the way your own prefernces and tweaks. Good grows and welcome to aero..you ll never go back
Werd, thanks for the advice Fletch.
 

QuentinQuark

Well-Known Member
Love my Aero machines.
Nice work with the chillers Earl!

I hope one day I can say that I love MY aero machines :)

Actually, I originally started this design with 8" PVC, but when I started reading I found all the info about giving the roots lots of free space and high-pressure low-flow aerosol nozzles and I ended up with my current design, which will be a single "box" 5ft x 6ft, 30" deep, sitting up about a foot off the ground and draining into a shallow collection tub that will have a pump in it to push the runoff back into the res once a day or so. Either that or I have the runoff draining directly into the nute res, but that means the box would have to be higher up off the ground, with the top of the box at like 4ft off the ground. That doesn't leave a lot of growing space in an 8ft tall apartment lol.
 

QuentinQuark

Well-Known Member
Well I said I would ask about the droplet size, and post the answers here.

Here's what FlexPVC said:

"> On the dropplet size.. I'm told they have not performed quantitative testing
> on droplet size and won't have that data any time soon. I think it's the
> same issue. At under 100psi, most all nozzles will produce the same size
> (about) droplet due to surface tension. To really atomize the water, you
> need the serious pressure to do that and the vast majority of systems do not
> have the high pressure pump."
 

QuentinQuark

Well-Known Member
And here's what Devon at KES Irrigation said about the droplet sizes:

"Unfortunately we have been trying for years to get information on the droplet size and different operating pressures. The manufacturer does not have this information and has advised it to be very costly and time consuming to retrieve."

Still waiting to hear back from one more party about the droplet sizes, but I can guess the answer... I don't understand why dripworks says it's a 55-micron if the testing hasn't been done :(
 

Atomizer

Well-Known Member
The guys from ShurFlo and Cloudtops are both correct. A bypass pump will be ok if it can generate enough flow at the correct pressure.You won`t need a check valve as most bypass pumps have a one way flow.

Biocontrols use 3 seconds/3 minutes,the Atomix uses a 2 second/60 second cycle.The goal is to minimize the misting duration but completely fill the root chamber with mist.
Good quality nozzles usually have a lab test report showing what percentage of droplet sizes they produce at various pressures.

An 80/100psi anti-drain valve as far as i know doesn`t exist so that may be an issue.

If you have 15 nozzles at 0.055LPM at 72psi and run them for 30 seconds you`ll deliver about 412ml of water, my 24 deliver 170ml for each 3 second pulse.
Most of the TAG pump failures you read about are designed with the pump doing all the work.

Matching a pump to the application is ok,it matches the flow and pressure but it doesn`t take into account the wear and tear on the pump especially for short mist cycles.
This is the reason i didn`t match the pump to the nozzles,if i had gone that route i would have needed a 3.4LPM @ 72psi pump..and perhaps buy a new one every a month :wink:

To get instant pressure you will have to have to use an accumulator tank, the pump charges the tank and the solenoid holds back the water until you need it..the distance from the solenoids to the mist heads is just a few inches, so you have instant pressure.
The tiny water volume in that interconnecting tube coupled to the adv valve means theres virtually no water flow as the pressure drops to the adv cutoff point so you have an instant off too.

The bonus of an accumulator is a much easier life for the pump. It simply recharges the tank,in my case it runs 8.5 minutes every hour. A pump without an accumulator would need to switch 20 times an hour to provide the same misting cycle and it wouldnt be at constant pressure. I guess my pump should last at least 19x as long.

I can set the tank pressure range to deliver 90-95psi,it would run upto 80 nozzles at full flow and pressure using the same 0.5LPM pump. The downside is the drawdown on the tank increases and the nozzles deliver more water due to the increased pressure so the pump would have to run for longer to recharge the tank. The pump is rated for continuous running so its not really much of an issue.

My vertical is a cylinder, its going in the greenhouse so i have the option of planting both the outside (big halide in the sky) and the inside surfaces (HPS). For stealth I could plant the outside surface with cherry tomatoes :wink:
Access isn`t too difficult as it 8ft diameter x 6.5ft high.
Heres the spec for my nozzles, they only tested them at 3 bar (44psi) and 4 bar (58psi) i run them at an average of 5 bar (72psi). The layout diagram shows how i`m arranging my aero, and the last pic is the vertical unit which is in the construction stages, its not exactly what you might call k.i.s.s but its definitely fun :mrgreen:
 

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QuentinQuark

Well-Known Member
Dammit! Just when I thought I had my design all set, you went and threw an "accumulator tank" monkey wrench in there :p

Well, I gotta think about this, it would be a bit of a sacrifice of simplicity, but it certainly would extend the life of the pump substantially. In all likelihood I will just go without the acc. tank, and keep a spare pump handy, so if I need to send one back under warranty I'm not out of service.
 

Atomizer

Well-Known Member
The ultimate accumulator tank setup for 24 nozzles would be a 250gal (950L) tank charged just once a day to 120psi.
It takes 24 hours to drop back to 70 psi with a 3 sec/3 min cycle. The downside is mixing the first batch of nutes but after that you only need to pump 20 gals a day from the return to recharge the tank back to 120psi.
Wonder if a hand cranked high pressure water pump exists? :wink:
 

QuentinQuark

Well-Known Member
Ok, something just occurred to me.

Rather than power cycling the pump every three minutes, couldn't I just put a solenoid between the pump and the nozzles, and open/close the solenoid every three minutes?

I mean, it's a bypass pump, right? So let's say it can do 1LPM at 100psi, and my nozzles only flow .5LPM at 100psi. So when the solenoid is closed, 100% of the 1LPM is getting bypassed, and when the solenoid is open, .5LPM is going through and .5LPM is getting bypassed.

But then you have the problem of the pump running 24x7... not sure whether they can handle that... maybe I can power down for a few hours during lights out? But that only works during flowering...
 

Atomizer

Well-Known Member
The pump will exceed its safe working temperature limit if its in full bypass for any length of time. The other issue is the initial pulse of water thats been looping inside the pump will probably be around 140F :wink:
I settled for the accumulator/pressure switch approach as it ticks most of the boxes i wanted and actually costs less the Smart Sensor type pumps that are sometimes recommended in TAG threads.
 

QuentinQuark

Well-Known Member
Damn, another great catch Atomizer.

I sent an email to the tech support guy at Shurflo asking him whether there would be any issue with power cycling a bypass pump every few minutes 24 x 7, they're the ones that would have to cover the warranty so I assume if that's not a good idea they will tell me!
 

Atomizer

Well-Known Member
I tried to cover every angle when i did my research, right down to droplet lifespan and drift distance :wink:
The most important question for most people is how much noise the pump makes, you`ll get some pretty vague answers to that one.
 
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