Hey KCCO 77!
I believe you may have had root rot (pythium) in your previous plants.
I'm on my fifth RDWC grow and had never had major ph drop like what happened to me recently. I'm in week six of flower, and had exactly your symptoms starting in week 3-4.
The ph dropped like a rock --as much as 3 points in 12 hours. The roots smelled fine, and as much as I could see the roots they looked like they always do. But the leaves were showing early signs of deficiency. Growth slowed to a crawl.
So I started googling and got very lucky to find a thread on RIU. Same exact thing! This guy tried everything but treat for root rot. He was convinced he saw no evidence of it. Lot's of people were trying to help him to no avail.
Finally, after more than a month trying everything under the sun, he got a recommendation from the help line at AN nutrients. The guy told him to do a 12 hour flush with 3% hydrogen peroxide (the drugstore stuff) mixed at the rate of 150 ml per gallon of water. Then feed low nutes for a bit. Long story short-ish, it solved the problem and he ended up with a good harvest.
I say I'm lucky because his struggle saved me a long slog of disappointing trial and error and google searching.
I did exactly this to my plant 2 1/2 weeks ago, and lo and behold no more ph drop. In fact, the ph is slowly rising between each day as a healthy plant should be doing. I think I'm looking at my best harvest so far!
Pythium is insidious. It's very hard to get rid of it. You must catch it early so it doesn't collect on all your equipment. It was good you cleaned your stuff thoroughly with bleach --some say the best recourse is to buy all new equipment. I won't be doing that
, but as soon as I'm harvested I'll be disinfecting my system --including inside my tubing.
So, keep an eye open for the possibility of it happening with your new plants. Good luck!
