Good day, I’m using a single bucket Hydra Unlimited RDWC system with a chiller inside of a 5x5 tent. I’ve had several past successful grows and harvests (but using a basic DWC setup)…so not a newbie, but not enough knowledge to resolve this persistent problem and desperately 'looking’ for much-needed help and/or any suggestion.
I’ve been using Advanced Nutrients pH perfect products exclusively and even over the past two weeks have had on-going ‘direct’ grower support from that company’s help line. My guy is skillfully trying to guide me through it but so far not seeing much change other than the behavior being slightly less aggressive, but same end result.
All my environmental controls (humidity, reservoir temp, ventilation, exhaust, adequate LED lighting, ambient temperature, and even VPD values) have been zeroed-in on to maintain expected ranges for a successful plant growth. My seed source and quality is trusted and legit (ILGM).
I’m growing a single plant. For grow process, I put a germinated tap-rooted seed into a properly pH’ed (5.8 distilled water) rock wool cube, then surrounded the cube down inside the net pot on the center platform using Tetrabase, which does not affect pH. I start out with the reservoir bucket filled with only 5.8 pH’ed distilled water.
Have been dealing with a persistent issue (and have now done 3 grow re-starts) and simply reaching out for any possible suggestion that could be the cause of my nightmare. The seedling sprouts out just fine with healthy cotyledons, and within 3-4 days fully develops first set of true leaves. And it is at this point that I introduce less than 1/2 strength nutrients into reservoir. Rez temps kept between 65-69 degrees.
Anyway, here is the issue…the first true leaves gradually develop little brown spots that continue to get worse until full leaf deterioration, but a new set of leaves will grow out above and eventually do the same thing and it continues. The leaves below the new growth continue to deteriorate and die off, and as new growth continues the same behavior is seen. Also my reservoir pH gradually rises but at an increased rate, but the nutrient strength (EC value) doesn’t fall as anticipated with healthy hydroponic plant growth and nutrient usage).
I first thought maybe a light temp/humidity thing but got that all honed in correctly. Then I thought it was nutrients being introduced too soon and so in one instance I started seedling out with even less than 1/2 strength. But even in one of the grow re-starts I delayed introducing nutrients several days thinking that maybe it was too soon and possibly that might be the issue. Still brown spots appear on the new healthy leaf growth, but old growth underneath eventually dies off.
Even though new, I’ve flushed my system, cleaned rez, changed out nutes due to pH rising out of range??? Like right now…at 3/4 strength nutes pH has gone from 5.8 to 6.2 in 2 days, but so far EC has stayed static at 1.3 
Roots are clean (using proper dosage of Hydroguard with each rez change), but I do kinda question the extent/degree of root system development at this point…but new leaf growth is impressive. Oh, I do have a CO2 mushroom bag going but have used them in the past without problems.
Again, at a total loss for a possible cause of this problem and just looking for possible solutions and any info, suggestions are appreciated. I’ve tried to be detailed/specific as possible. Plant is about 3 weeks old and sooo far behind.
I’ve started over 3 other times and it would be hard to convince me that putting the tap-rooted seed into rez to sprout has some kinda impact. BUT I’m wide open for thoughts, suggestions, ideas. This is a vital test grow, so I can confidently replicate; and can’t wait to revisit LSD…ah, what an interesting crazy buzzz! 
Or If anyone knows a legit cannabis botanist, holler! IMG_7998|375x500
