Ok, I promised a parts list with links, and this is it...
Root chamber: I deliberated the most about this. I concluded this deck bin storage box was ideal because it gives plenty of room for the mist to expand and spread out and had dual-wall construction, so it is inherently insulated with air, and I can drill some holes in which I may spray low expansion polyurethane foam if I find the need for more insulation. As mentioned before- I plan to cut out a root access door on the front for viewing the roots and messing with nozzles as needed without having to lift the whole hinged lid. I plan to drill out 6 staggered net pot sites so they have plenty of room, but in a sog setup could probably fit a bit more sites. The sun in the tropics is 12hrs daylight (perma-equinox) throughout the year with only an hour more or an hour less from summer to winter solstice, so if left only to nature, I will always go straight to bloom outdoors and perhaps the sog setup configuration would be better for my situation, I suppose it's easier to add holes than plug unused ones, so I'll start with less holes. I wonder how this will work out as I've never grown outdoors here before? The floor of this unit is slatted, with each slat butted right up to each other and I'm trying to decide if I should silicone it watertight except for a small drain area, or just let it be and put a liner pan underneath to catch the runoff. I'll figure it out after I see how the mist works in there. The website currently lists it for $114, but my local Home depot has it for $159 (we call this the "paradise tax").
http://www.homedepot.com/Storage-Organization-Sheds-Garages-Outdoor-Storage-Deck-Boxes/h_d1/N-5yc1vZbtz1/R-202046946/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053
Pump: I opted for a 12v Flojet because I felt it had the best specs and I want the whole system running 12v for safety, and also so that I can use a deep cycle battery (with a trickle charger or perhaps a solar charger?) running everything to keep it reliable regardless of what the electric company here is doing. I went with 150 psi pump because my target pressure to run the system at will be 100 PSI. This will allow roughly 50 psi of stored nutes to be sprayed until the pump recharges the system again. I will use a pressure regulating valve to keep the misters output at a constant 100 psi regardless of the status of the accumulator's charge- as to keep more control over the mist which would change over the draining of the accumulator pressures between 150 down to 100 psi otherwise. Most diaphram pumps in this pressure range are very similar, so it should not matter that much. I have yet to see anyone use a flojet in aero, but Sureflo is common, and I hear the Aquatec 6600 is virtually silent. I will have to report on the sound from this pump after I try it out. I found it by luck for $75 on clearance, but that was a one time deal.
Manufacturer's link and specs:
http://ittflowcontrol.com/files/itemdoc11231.pdf
Best price here: (but manufacured to order which takes 4 weeks):
http://www.dultmeier.com/products/search/7462
Average price, but they have it in stock as well as hundreds of other pumps here- this site could come in handy in the future:
http://www.wholesalepumps.com/index.php?p=product&id=228&parent=8
Accumulator: Most are rated for 80-125 psi unless you wanna spend big bucks. This one I happened across was a no brainer as they sported some of the cheapest prices around, and it is actually rated for max 150 psi. No other regular accumulators were rated this high, so it's the dog's danglies! They are steel tanks coated inside with plastic to resist the nutes and rusting, and have the typical bladder arrangement. They're actually designed as thermal expansion tanks that also double to use as accumulators, and this is why they are designed for the higher pressures. It is fair to note that anything smaller than the 10.3 gallon tank is designed to hang upside down by the pipe by which it's connected to- not what I wanted for this arrangement. The larger ones (10.3 gal. and up) are manufactured with a metal ring stand on the bottom and designed to sit upright like a bbq propane tank- perfect for this project. They also are running a deal on a 30 gallon model for only $200usd- not bad! That larger size would allow me to run a week or more without the pump running, but I figure I might be playing around with the nute ec levels a bit to start and don't want to bother with draining the many gallons of pressurized nutes back into the reservoir constantly. More than one tank can be easily added in series, so I can always upgrade or add on later if I need. I should still go a couple days or so between the pump coming on with the 10.3 gal. and that's fine by me.
Here is the whole lineup, (I got the ST-25v for the record):
http://www.pexsupply.com/THERM-X-TROL-Tanks-354000
Pressure Switch: Well, the pump I bought comes with it's own pressure switch. I hear that the pressure switches that come with the pumps are low quality and besides being innaccurate, will probably not last very many cycles. The deadband (the range between cut in and cut out pressures) was also quite large and unadjustable (cut in 95 psi/cut out 150 psi). I was looking to cut the wires off of the pump's switch and route them to this (hopefully) better quality external switch that meets my needs. I would prefer to set the cut in pressure at 110 psi (10 psi above the regulated pressure to the nozzles)- and cut out at 140 psi (10 psi less that the accumulators max safe operating pressure for safety- and hopefully to not completely stress out the bladder to it's max constantly). This one by Dwyer I am not sure about the quality, but it was quite a bit cheaper than some of the $100+ models and claims accuracy of +/- 5psi.
http://www.amazon.com/Water-pressure-switch-35-150-2-4-10-3/dp/B00481QFQK
Pressure Gauge: I wanted to always know what the unregulated pressure in the accumulator was before the pressure regulator, so I'd know where the accumulator stood in terms of charge and also to make sure the pressure switch was indeed functioning properly. I decided to go with an oil filled model because the needle will be alot less jumpy during pump times. It reads up to 160 psi and I'm not bothering a link because it's simple enough and any gauge capable of the correct pressures that's rated for fluids will do.- I paid $12 for it on Ebay.
Pressure Regulating Valve: As mentioned above, I opted to add this piece to keep the misters always operating at 100 psi. It is stainless construction, adjustable from 0-150 psi and includes a pressure gauge to display what the new regulated pressure is adjusted to. Conveniently enough, it has a 1/4" john guest output. I am also not including the link, but it's simple enough to find a suitable one. I found it on Ebay for $35.
Pressure Release Valve: Since the accumulator is like a bomb and will explode if overpressurized by the pump in case of a pressure switch failure, this little piece is of major safety importance! The one I found was stainless construction, and adjustable up to 150 psi (where I will probably set it). It has an output port where I could route the blow off pressure back to the res, but I don't plan on it ever cracking open unless in a pressure switch failure- where the bleed off will be the least of my problems. I guess I'll route it back to the res nonetheless, just incase it does happen to go off continuously while I'm away and then my nutes will not run dry and all the plants die. I found it on Ebay for $13- very cheap insurance... It's fair to note that the PRVs with the metal pull lever made specifically for hot water tanks are not ideal in this situation. Get one with an adjustable screw.
Tubing: I have read that John Guest (flexible PEX tubing like what's used on reverse osmosis systems) is by far the best way to go for this project. PVC is too large a diameter and strectches too much under pressure. John guest tubing is rated for 230 psi at 70f degrees and is very simple to connect and disconnet via their pushfit speed connections. The tube is also not rigid like pvc and can be flexed and curved in the run as needed. I am using 1/4" diameter throughout since the flowrate for this project is quite low, and at the nozzles I will have more control of the dripping with a smaller pipe size. I hear I can run quite a bit of nozzles off just this diameter, but someone with more needs may choose to run the 3/8" diameter or bigger up to a manifold or solenoid, and size down to 1/4" after each solenoid up to the nozzles. I opted for the black because it is the only one that is UV stabilised, and mine will be in the sunlight. I'd rather use white for heat reasons, but not cracking in the sun is probably more important. In either case I may cover them with a conduit anyway- if I need to cool the solution just before it gets sprayed. It's fairly cheap @0.20/foot, but I happened to find a plumber on Ebay selling an assortment of leftover 10- 15 foot lengths (200 feet total) for a mere $12. That should be enough for all my future hp projects for years to come.
Timer: There are a few options out there. Because control is one of the most important aspects of this type of growing, a good timer capable of a resolution of 1/10th seconds is ideal. Those art-dne timers are not recommended as I've heard too many complaints of them failing, and I do not believe they go down to anything less than 1 second. The Sentinel DRT-1 timer also has bad reviews and besides only being capable of 1 second increments, it's reported to not be very accurate at the 1 second level anyway. I have been told that the ATC 422 flip flop timer works great and seems to last, so that's what I went with. It is available in any standard ac/or dc voltage too. There is an octal base needed to mount it, so don't forget that as well (listed at the bottom of the same page). Timer: $91 Base: $6
http://www.iseincstore.com/422_timer.aspx
Solenoids: There are a ton of options and a huge price range. What we are looking for here is a solenoid that matches the voltage you'd like to run in your system (12v dc in my case), can withstand the regulated system pressures, and is "normally closed" (meaning it only opens when the timer sends voltage to it momentarily for the spray). I went with a cheaper option and hope I am not disappointed. I opted to get 1 solenoid for each nozzle because the longer the tube run between the two, the more chance for expansion issues where the nozzle will spit and drip before and after misting cycles. Here is what I found for 14.99/ea:
http://cgi.ebay.com/1-4-Plastic-12VDC-Electric-Solenoid-Valve-Water-Air-/140521315257?pt=LH_DefaultDomain_0&hash=item20b7b91bb9
Nozzles: There are alot of choices out there. And for varying needs your choice may be different. tree farmer recommends bio controls as he seems to get some very good results with them, so who am I to do different? These are an impingement style nozzle that breaks up the water stream when it hits a small pin attached to the outdside of the nozzle. They are plastic and very low flow. I think I'll need 6-8 for my chamber, so I will just order 10 to be safe, as tree farmer also mentioned that about 1 of 10 have a bad spray pattern due to errors in manufactuing. They are $9.99 for a set of two nozzles.
http://www.biocontrols.com/secure/shop/item.aspx?itemid=85
Misc: Other things I'll need are:
1) A reservoir- just about anything that holds water will do. The daily throughput of my system should only be a couple gallons, so 5-10 gal size should suffice. I may chose to use an ice chest to keep the nutes cooler in the daytime temps- and perhaps an air pump/powerhead just to keep it from stagnating. (The plants will recieve all their necessary DO from the air in the rootchamber).
2) All of the John Guest fittings and adaptors, valves and tees for all the plumbing. They are not exactly cheap at $3.50/pc for a JG tee, and may add up. But I'll happily pay for the convenience they offer as opposed to other options.
3) I will also need some wiring for the electronics and crimp on connectors, the wood to build a box for all of the main plumbing and timer controlls, and some silkscreen/capillary mat to suspend in the bottom of the chamber suspended to keep the roots out of the drainoff. I'd estimate these parts to cost $150 or so.
Root chamber: $159
Pump: $75
Accumulator: $106
Pressure Switch: $29
Pressure gauge (for the unregulated accumulator side): $12
Pressure Regulating Valve w/ pressure gauge: $35
Pressure release safety valve: $13
John guest Tubing 1/4": $12
Timer/base: $97
Solenoids: $120
Nozzles: $50
Misc: $150
-Cost for a pimp ass aero system? -PRICELESS!
Hehe ok- so grand total for me is: $858 (plus whatever shipping charges)
It's not the cheapest route, but remember it's more FUN, yeilds better growth in a shorter amount of time, is easier to run once dialed in and will eventually save you alot of money in nutes!
Phew, that was alot of work, I hope it helps someone out to understand what this system needs and the rough estimate of costs.