first grow (nft), problems

Hello I am new in this forum, you pardon my English because I am Spanish, to question: it is my first culture in nft, to cultivate 12 clones ww and 4 of sherezade, in growth the plants to grow very well, beginnings of equal flowering, but to the 20 days of flowering they begin to deteriorate the leaf and not to create dwell flowers, the pump 1000L/H =16L/M, after the plants many roots the level of the water to raise flooding the roots completely, can be that the problem of my plants? Every 2 days I add liquid oxygen(h2o2 17%) in tank, I leave photos that an image is worth but that thousand words, greetings from Spain

space = 1,50mx1,20m
power=1000w hps
system= nft tank 100L
tª ambient =25-26º ( air conditioner)
Tª water =24º
Fertilizer = gh flora series+nectar diamond+green hope root stimulator+gh bloom stimulator+delta 9 (bloom stimulator foliar)+oxy plus ionic(h2o2 17%)
Humidity=70%grow,30% flowering
Air pump=2x90l/h
Pump= 1000l/h

grow very good
[attachment=o71572]

beginnings of flowering perfect
[attachment=o71573]

the end :confused: :confused: :cursing: :cursing:
[attachment=o71574]

If I understand you correctly, you are 40 days into flower. If so, your plants look completly normal for many varieties. It is very common for leaves to yellow during this time. It is the plants last effort to put every bit of energy it has into making the buds. That's it's lifes goal, so it is actually eating parts of itself that are not as important as the buds are. There is nothing you can do about it.

And welcome.

Oops, I just took a closer look. Seems like the yellowing is mostely near the top. If this is the case it is definately possible that you are getting heat damage. Have you measured the temp at the top of your plants? You may want to try pulling your light back a little or putting another fan on them.

Nice looking grow. Good luck.

pardon, the plants already are cut

the roots final
[attachment=o71592]
[attachment=o71593]

25 days before
[attachment=o71594]

That's really cool. I love the way the roots are exposed to air. I would love to do a true NFT, but I have power failures here, sometimes long enought that the plants would die. I kind of do a hybrid style of NFT with a reservior at the bottom of each plant to keep the roots in moisture, even if there is no power.