manganese toxicity or what?

wow, good to know. I've got two strains going in this grow, mandala #1 and these blue mystics. The mandala I grew last winter I had nute level at 1450ppm and they took it. The blue mystic is a new strain for me, so I have no idea what to expect. 2 of the 5 mystics are showing the problem photoed, the mandalas are looking great, so maybe you've pegged it and the mystics just aren't high nute plants. I'm backing down to 600ppm and we'll see what happens.

funny thing is I grew Nirvana's white widow on that same grow with the same nute solution (1450+ ppm) and I don't recall any burning or problems with the plants, yield was a little light compared to the other strains, but white widow is definately a bomb smoke. Can't wait to grow it again soon. Also grew Kannabia Smile (a freebie seed from the Attitude at the time, I'd recommend it also) and some Lemon Skunk I'd grown before. All the plants were great except the skunk, which had been a proven performer in previous grows but was horrible in this one. It grew fine but took forever to finish and the smoke is awful. Tastes like shit, no thc, awful. I still have a jar of it sitting around because I don't even want to smoke it. No idea why it was so bad, like I said it had been a winner in previous grows. Guess it goes to show how much I have to learn. It makes me wonder if it was too high a nute that made it so lousy. I flushed it for 1+ week before harvest but still god-awful.

Subbed ... I want to see how it all works. I am intrigued that your Nirvana WW and mine had such very different nute requirements. Then again if Brick Top is right, Nirvana's phenos aren't the most consistent. Anyway, subbed, and best of luck. While I sit in the Remedial Soil Grower's Corner I'll vicariously grow hydro here ... cn

haha, I'm a farmer by trade, so growing in hydro is a weird obsession/hobby with mine since I work acres of soil outdoors, just not for growing cannabis. I do grow some outdoors in the summer, but always lose track of it and get poor results due to lack of attention to the plants. I find growing indoors allows me to (obsessively) micromanage the plants and gives me something to do all winter when I can't grow anything outside.

update: necrotic spots on the leaves have stopped spreading on the 2 plants that were showing them. New growth seems a little slow, but maybe I'm just being impatient. The leaves on all the plants seem to be curling down so that they're 'huddled' close to the plants' stems. Water temps in the reservoir is now 70 degrees, apparently the foil tape has helped to cool that off considerably. The weather here has also dropped 10 degrees, which helps. Temps in the grow tent have been in the mid 70's rather than mid-to-high '80's. I'm starting to see lots of branching at the plants' nodes.

Update: finally have gotten my issues narrowed down to ph problems-- my ph was too low (5.2-5.5). Adjusting the PH to around 6.0 has seemed to solve my problems. I also went back to the normal Genhydro feeding schedule rather than the "Lucas Method." Not sure how much of a factor that has been in my plants' recovery, but the PH was definitely the major problem. Moral of the story (for me at least), keep your PH meter well adjusted and tweak your PH to the other end of the spectrum if you start seeing problems and think you've got everything else sussed out. I was able to see changes to the plants in about 3 days time. They're back growing like they ought to, even though I'm probably 2-3 weeks behind schedule and now need to decide whether I want to keep them vegging longer or if I should flip to flower and just have some really scrawny plants.

Pics please! cn