In my opinion, when it comes to over watering, the container that you use is not as important as the medium you're utilizing. The medium you're using HOLDS water, so watering will not be as regular as say someone who uses coco. I use the "lift" method. I pick up each bucket to get a "feel" for whether I need to water or not. ALWAYS watch your plant. Learn to "read" her. She will tell you EVERYTHING. This is a teachable moment for you. Now you know when she droops like that, she's telling you something - most likely she's been over watered. Again, this is just my opinion based on MY experience. It'll get better, trust me. Good luck moving forward.
Higher temperatures also mean less dissolved oxygen in the water and medium in general. Its kind of a lose-lose situation.
The plus side on grow bags is that if you have a lose enough mix, you can massage the bag to loosen it all up. I would strongly recommend gently doing so if you can. In the future, I would say to go with a looser mix.
My current mix is 6 parts coir, 4 parts perlite, 4 parts verm, 2 parts worm castings, 1 part peat, 1 part gypsum/lime/silicon dioxide(kitty litter crystals), and 1 part random mix of leftover fertilizers. Its way better to skimp on food than it is to skimp on air. Roots can grow right in pure air if conditions are right, but they can't form in pure food no matter what you do.
I m deeply appreciated for your help.
If you dont mind, i would like to have your opinion about my light setup since it is the main source of heat in the system.
In vegetative stage i used 9*14w 1521lumen 6500K led screw bulb, for a couple of days i switched to 9*11w 990lumen 3000K led screw bulbs. I m thinking maybe i should decrease the number of the bulbs from 9 to 5 and put 30w led bulbs. Surface are of my stealth box is 50*70.
You burnt those plants when you altered the pH with vinegar and then over watered. I like to keep the container size small enough to only hold 7 days of water. It the pot needs water before 7 days, like in "4 days" I would transplant into a slightly larger pot. Keep the containers small to better manage watering and this won't happen. Your containers are too large and won't dry out before 7 days. Also get yourself a liquid pH meter and keep the pH in check and throw away the soil meter with probes because they aren't accurate.
At some point its going to require either a reduction in heat output or an increase in air exchange. A sealed system definitely has major wattage limitations.
Are you talking centimeters when you refer to your space? If that is inches, that space is huge. Otherwise your 118 or so watts is probably more than you need in that space.
So that space, if I am calculating correctly, is about 3.75 square feet. That means your 118W is about 31-32W per square foot(sorry, I have to convert it because that's what I am used to). That's actually not as bad as I initially thought. Still, I wouldn't raise the amount any. Just increase cooling asap and massage those bags. If they're dangerously ill, transplanting them into a looser medium might save them.