OK, What problems have I encountered and what was the solution?
RH - I started by maintaining RH at 80% from the start of seedlings. I think it was a good idea for the seedlings, Not so much for veg. The plants were not breathing and thus not drinking which led to my next problem. Root snot.
The VPD charts can be misleading if not understood. I am now maintaining 66-68% RH in both tents. You can see the result.
Root snot - I call it snot because it did not display the bad smell and rotting of the roots. Rather it would begin with a clear slime on the roots. It would eventually develop into a brown algae slime. Solution?
I did a complete system clean of all components 7 times now. Why 7 times? Mostly I was chasing a symptom and not correcting root cause. Root cause was stagnant water in res (no drinking) combined with res PH rising every day.
Quick rundown of complete res change and cleaning of an auto feed MicroOcto pot system:
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First time took at least 4 hours. Now I can do it in 45 min
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Take each top pot and place on a box so net cup and roots have somewhere to hang.
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Shut all valves on entire system.
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Disconnect each res hose forward of shut off valve for mini res.
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Dump each res intro toilet. Dump control, then main.
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Choose cleaning solution dujour. I’ve used 3% H2O2 diluted with RO water, 7.5% bleach diluted and finally Hypochlorous acid at 2ppm. The 2 PPM level did not kill any plants but much higher than recommended.
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Fill main with cleaner, dump and refill after cleaning, dry w paper towel.
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Same on controller. same on mini res. Make sure to open valves when dumping to clear any residual nutrient solution in tubing.
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Secondary flush of entire system from main to controller out through each tube via manifold verifies all orifices are clean and flowing well.
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Clean tent surfaces before placing system components and reconnecting.
PH control
I’m still working on this one. I have begun hourly PH checks on all mini res. The PH is easy enough to maintain if checked often. Overnight, I am seeing drift from 6.0 to 6.3-6.7. Correction sometimes takes up to 16 drops of PH down in one mini. At least the PH is being maintained at proper levels most of the time.
I am still not certain why I am seeing such drift. Possibly Jacks 20-20-20 being mixed too lightly. Current run had .75 tsp/Gal. Will bump up to 1tsp/Gal next fill.
The Auto tent does not experience such large swings. Worst case I see a res or two that need a drop of PH down in the morning. Running auto tent with Jacks 10-30-20 .5tsp/Gal
Any insights into PH control issues appreciated.