Here’s a response I got from ic mag forum:
[QUOTE=growaway;7244693]Nice stealthy little setup ya got there friend! Looks a little like early sequestering of nutrient from your foliage because of root zone uptake issues. Lots of anthocyanins in your petioles and stems too. This could be strain related but given your other symptoms i hazard its all related. ‘P’ lockout secondary to cold air and/or nutrient temps and salt build up are commonly the cause of this for me. I agree with other members that N uptake is also occuring so salt build up is prob more likely of the two. I can see a little salt build up on your expanded clay also. Calcium sulphate most likely. Check your minimum temps and solution temp are not too low and give the system a “flush” and then feed at normal strength again would be advice. Your bud development seems reasonable so unless she defoliates rapidly, you should be ok. Love to see some follow ups if you get a chance. Cheers.[/QUOTE]
I posted this question to two other forums, and I got about ten responses in total with possible issues ranging from: PH too high, PH fluctuations, too much PH down, feeding too much, feeding too little, poor nutrient brand choice, K deficiency, Needed CalMag, too small of a space, too high (or low) ppm, air pump too small to aerate roots, and Nutrient uptake at roots.
It was a little frustrating to get so many contrasting responses, but it prompted some research on my end, and I am inclined to agree with growaway’s response.
Here’s a little more info: My reservoir and air temps are both 77.9°F. I have always used 100% RO water. My roots do appear to be showing some signs of rootrot, although I can’t be sure that they aren’t just stained from nutrients… I have attached a couple pics of the roots. Do these look rotten?
I know in future grows, I will add additional air stones in the reservoir. Does Hydroguard do anything to prevent or cure root rot? Also is 78° too hot for the reservoir temp? How long should I “flush” the system, for a day? Or should I just keep running clean water through? Also should I clean out the reservoir?
Thanks all for the info! Any other advice you can provide would be helpful.