Phosphorus or Calcium?

[Geodawg22]

Hey Everyone,

First time grower running into an issue that would like to get some input.

System: High Pressure Aeroponics 100 PSI sprayers with a recirculate system. Spray, drain back to reservior. Accumulator and pump, 3 sec on, 2 min off cycle

Seed:
germinated in rapid rooters 4 weeks ago
Auto white widow (progressive symptoms)

Photoperiod topped white widow(starting to show symptoms)

Big Bud XXL not showing any symptoms, even showing excess nutrient

Nutrient:
RO water 0 EC 5 gallons, Dutch Masters Gold Veg 1/4 nutrient strength, added CALmag 3ml/gal, added drip clean 0.4ml/gal
510ppm(.72 EC) 5.9ph

Light:
DIY 4' Samsung LM561C LED 18" away from top of plant (18/6)
500 PPFD currently

Room:
sealed room with multiple fans and swamp cooler to bring the humidity up, I am in southern Cali so it gets dry and hot.

Temp/Humidity

I'd appreciate any input on my setup and issues.

-Geo

 

[Geodawg22]

Updated with more pics. Any help would be greatly appreciated!

The main Auto white widow with the issue

2 smaller plants I topped are also showing progressive symptoms

 

[polishpollack]

you see those red spikes on the temp graph? that's your problem. since you have a swamp cooler, I'm guessing you don't have A/C.

 

[Geodawg22]

Hey Polish, I can't quite get the heat from LED out the room yet because I need to install a hole to exhaust the hot air. I do have AC, but rest of house is cold hence it's not turning on. In the day if it's always on, the temperature stabilizes at 80F even with lights on.

For the most part the temperature will stay around 85 when LED have been on for a while. I thought they can handle the that temperature, or are you saying it's the big ups and downs throughout the day causing this issue?

 

[polishpollack]

Just the ups that are every day. more fan action then.

 

[Geodawg22]

I am now seeing what I believe to be is root rot. The temperature as been too high and lights were able to penetrate the lid (didn't paint it yet). You can even see the green algae returning to the reservoir.

 

[Tim1987]

Yo Geo,

If i can give any advice, its to do a complete reservoir change, and rinse your net pots. Add some beneficials to your reservoir. Fix that light leak.
Get the temps under control ASAP. Ice bottles, aquarium chiller, whatever...
Change out, and rinse everyday if need be. It'll recover, ain't too bad at all.

How stable is the ph?
Are you adjusting all the time? If so, in which direction?

I've had these exact symptoms on my fan leaves, from too much calmag. It looks like calcium deficiency, but it isn't. Then we add more calmag, and it gets worse.
All the calcium is being antagonized, and getting locked out somehow.

What is the ph of your reservoir? Is it continuously kept at ph5.5?

Ec/ppms?

Nutrient NPK total?

NPK of your calmag?

Supplements?

 

[zypheruk]

Roots look ok except for the algae, some h20 in the res to clean of the roots. Refill carry on as you where and as above forget the calmag, your plants will let you know when and if you need to add any.

 

[Geodawg22]

Hi Tim, Zypher,

Thank you both for the advice!

How stable is the ph? Are you adjusting all the time? If so, in which direction?

I just mixed up a new 5 gallons worth of RO water with 0 ppm, added cal mag to 300ppm (x700 EC), then added A+B dutch master gold to 500ppm, PH is 5.8.

usually a day later it will be at 6.0, then 6.2 the next day which I use PH down to bring it back to 5.8 again. (I've always had to adjust down due to the PH rising everyday by .1 to .2

Nutrient NPK total?
Dutch master gold grow A 3-0-2
Dutch master gold grow B 1-2-4

NPK of your calmag?
It's just cali magic 1-0-0

Supplements?
Drip clean .4ml per gallon (to prevent clogging)

I have some hydroguard on the way for tomorrow so hopefully that will help.

 

[Tim1987]

Hi G,

NPK of the AB seems fine to me...4-2-6 is your total. Thats pretty good for early veg imo.

I'm gonna be straight with you...that's a shit load of calmag. There is more calmag than NPK in your reservoir. To me this is a glaring issue.
Also the EC its too high. 1.0EC is a lot for plants this small.

My suggestion is to cut the calmag right out.
Have faith in your base nutrient. I'd try 350-400ppm of your base, and cut out all the calmag.
The calmag is causing your issue. I'd bet all in on it.

The ph seems ok.
My thoughts were, if your reservoir was at ph5.5 all the time it locks out calcium.
At ph6 or 6.2, calcium is very available.
There is more calcium than npk in your reservoir. You are not calcium deficient. No way.

You are practically turning your RO into hard tap water, using all that calmag. You may as well be filling up at the kitchen sink.

Sorry, just being honest mate.
I'd put money on this being your issue.

 

[Geodawg22]

Hey Tim,

I appreciate the honest feedback. You don't have to apologize for giving it to me straight.

I will mix up a new mixture tonight. My EC is .71 since it's 500 ppm on x700 EC. What should I bring my EC to with just RO water and the A+B(4-2-6)?

-G

 

[Tim1987]

Hey Tim,

I appreciate the honest feedback. You don't have to apologize for giving it to me straight.

I will mix up a new mixture tonight. My EC is .71 since it's 500 ppm on x700 EC. What should I bring my EC to with just RO water and the A+B(4-2-6)?

-G

I reckon, 0.8 ec or just under. 0.7 or so sounds good.
Better to start a little lower, you can always add after.
350-400ppms. Somewhere in that vacinity.

Yep just your AB for now.

If you check your nutrient, it probably has calcium somewhere around 3 or 4%, and magnesium somewhere around 1 or 2%. This will be fine for now. Iron will be fine too.
You may need to add a small touch of calmag in a couple weeks, once they've vegged a little larger. But for now, your AB should be absolutely fine.

To give you an idea, my own plants right now, are in their first week of flower, and are still only at 1.1ec.
Admittedly its coir, not pure hydroponics. But my waste reads the same as im putting in. Plants are much larger too.

Go easy on the nutrients imvho. You can always add more.

Best of luck, keep us all updated.

 

[Geodawg22]

Hi Tim,

I just prepared a new 5 gal solution with just RO water and A+B nutrients 0.71 EC with 6.2 PH. Then I used PH down to bring ph to 5.8. The other thing added was .4ml/gal of Drip clean.

The A+B comes with 4% calcium and 1% magnesium.

Current ppfd is 545 using a lux meter/67.25, conversion is from quantum boards v1 which uses the same Samsung diodes as my strips

I also dialed in my temperature with a nest temperature sensor just for that room; best 40$ I spent. You can see the lower temperature during my dark period of 2-8pm.

Tomorrow I will add the hydroguard to the nutrient solution and paint the top of my tote so that no light can get into the root chamber.

Thanks for all the help!

 

[Tim1987]

Not a problem dude. Hope it helps.
4% calcium is pretty damn good.
If the plant doesn't take the nutrients too well first off, just dilute it to 300ppm or so.
It should be swell. But just keep in mind to go lower, before going higher. The plant wont die, adding more water.
Tip the plant over the edge with nutrients though, and it will.
Just give it a few hours. If it starts perking up, and looking happy, you should be golden.
If it starts slumping, then dilute the reservoir a little.

All the best, and i'll await your next update.

Tim.

 

[Geodawg22]

Last night I mixed up a new solution with .71 EC and 5.8 PH

Earlier noon the reading was .7 EC and 6.1 PH, I also added the Hydroguard which didn't disturb the readings

Tonight 8pm it is reading .671 EC and 6.3 PH, should I let it sit or Ph down it to 5.8?

Overall it seems the plant is happier and growing, the green algae is being dealt with and spots on leaves looks to be contained...

 

[Tim1987]

Hi Geo,

Good news. Sounds good. Seems to be liking it.
Yeah thats what i would do. Just adjust it to 5.8 again.
In a few days, if the algea is all but gone, and the ph is still rising a little quickly. I would feel pretty confident in upping the ec of your AB a little.

Cool idea, you had for the setup too. I like it.

Glad the plants seem to be improving to you.

 

[Geodawg22]

Hi Tim,

I adjusted the Ph down to 5.8 last night and had an EC value of .686

Today(24 hours later) the Ph is reading 6.1 and I have an EC value of .614, I will bring it down to 5.8 now. I also notice my water level is going down which means they're drinking plenty.

The Hydroguard seems to be working since the algae growth has been limited, but they could still be healthier.

Thanks for all your support,
G

 

[Tim1987]

Hi Tim,

I adjusted the Ph down to 5.8 last night and had an EC value of .686

Today(24 hours later) the Ph is reading 6.1 and I have an EC value of .614, I will bring it down to 5.8 now. I also notice my water level is going down which means they're drinking plenty.

The Hydroguard seems to be working since the algae growth has been limited, but they could still be healthier.

Thanks for all your support,
G

Not a problem dude. Sounds like you have things under control.
Don't hesitate to ask my opinion if something else creeps up.
Thanks for all the handy information you supplied man.

 

[polishpollack]

Lower water level might be due to evaporation rather than uptake. You've said that it's been warm in the grow space.

 

[Geodawg22]

Hi Tim,

I have some bad news. The root algae is still present, I need to get a couple more layers of paint on my lid so no light can hit the roots.

As for the spots on leaves, they're still present and seem to be back too. I am taking your advice and added a gallon of RO (0 EC)
and ph down to bring it to level.
Before: 0.557 EC 6.1 PH
After: 0.457 EC 5.8 PH

My biggest question is whether or not this is caused by too much nutrients or the root algae.

Hi Polish,
The temperature has been dialed in for the past couple of days.

Once again, appreciate all the help guys!