Death appears imminent

I am new to hydroponics, to be honest not sure what it's called.
I have a 600w light over 9 plants. Plants are in 6in pots I think sitting in a 3'x4' tray with a drain hole sitting on top of a black 50 gal. Or so res. I have an air stone in the res and a pump on a timer the runs water from the res. In a single 1/2" line with individual lines going to stakes in the pots.
I have been running the water to the plants for 30 minutes every 1.5 hours. I was supposed to move them to another location weeks ago considering they are 2.5 months in my place. My grow space is very limited.
I battle temperature and humidity. But thus far my plants have thrived. Two weeks ago I topped them and put them on 12 and12 . Again it's just because of circumstances and timing that I topped them at that time.
All of them except 1 have grown like crazy one didn't grow at all where I topped it. Now for two days its been dropping all the leaves straight down.
The one plant only is dying I think. They're some fruit fly type bugs.

My thinking is the small pots root bound it now it's rotting. Oh the medium is grow stones.
It's just affected the one plant.
Hydrogen peroxide? Just get aqua shield tomorrow?
Also I have springtails in the res.
If the pics are sideways I apologize.

THANKS

Way to small of pots. Use h2o2 and that will help a little. How far away are you from finishing?

i thnk you have root rot. are your roots brown and mushy? the bugs are probably fungus gnats they love dead roots.

Nice stems.

Why it sometimes uploads my photos upside down I don't know.
Transplanted 4 of 9 last night. Including the deathbed plant. The bottom sets of leaves are drying and dying off. The new growth at the top may be showing life.
The roots didn't look to bad.

I have been running the water to the plants for 30 minutes every 1.5 hours

Click to expand...

That's far too much and they are overwatered.

I would run for 30 min every 4 hours

Plant looks super sad... Clearly not taking up water. Spray the leaves to hope they absorb some and see if you can't get the roots drinking again. If you can't cut the plant so problems don't drag your grow down. If its not healed quick its prolly gonna be stunted. H2o2 may help, maybe

Okay I can change the water schedule but I will say the roots looked healthy and the plants beside that one are prosperous. I'll change it today. Think the one is a lost cause. I can deal with that.

Alright great people I've decreased my watering. I decided to just pull that plant.it was using valuable space in my room. It probably would have recovered but not in time and such. Also all eight will be in bigger pots by days end.
Going to pump out my rez. And refill tonight as well. Three of them are 5 feet from tip to top of the pot. If they stay any longer than another 10 days I'm putting a 1000w on em.
I am watering from the top with 360 sprayers. Haven't seen any pics of a setup like mine.