Man once you set up a re-circulating system properly ... i beleive its the easiest system to maintain .... you can go away for a few days or even a week with no big dramas .... i like to top feed with ring sprinklers in expanded clay .... i use pots with holes in the bottom that sit in a tray .... same equipment as flood n drain except i top feed with it using pots ... the water runs out the bottom of the pots and down the tray ( which is slightly raised at one end) to a drain plag at the end ... the water then falls into a resevoir below .... which contains a submerable pump conected to your feed lines, ready to be pumped back up again .... (i am sure you know what i mean man iam dribblin just in case) .... when i first put in my clones i have them watering constantly for 10-14 days till my roots spread out a little bit ... then i connect my pump to a peg timer and water 15mins on 15 mins off ... for about 2 weeks ... then 15mins on 45 mins off ... once the roots are pumping .... the more roots the more moisture your pots will hold for longer (in clay) ... so you should definately slow down the watering as the roots grow bigger or you'll encourage root rot by drowning the roots ....
with the temp in your grow box man ... the surface tempreture of the leaves can get way hotter than the room temp ... if the side edges of the leaves start curling upwards (and the tip of the leaf may or maynot curl downwards) their surface tempreture is way too hot and needs fans blowing across the top of your canopy ... constanly pushing the hot air off them ..... i am just guessing man cuz there are no pics ... paste some pics with a digi
Also man what is pro soil ?????? .... ooooo also the core temp of the pots makes a massive difference .... 18-22o celcius is beautiful (whatever it is in farenhite) ... ever buried a digital tempreture probe in your pots to measure core soil temp ?... its better than guessing man .... cost about 10 bucks ... one thing people should spend money on is equipment to measure all aspects of their enviroment ... if you monitor and maintain everything correctly ... your meters should give you a pretty good idea of whats going on .... This pro soil has me thinkin .... but using the same soil under less intense light and they go fine .... sounds like heat and air issues .... also check your roots to see if they are white and healthy .... shitty roots grow a shitty plant man .... brown roots would be generally over-watering or soil temp .... water can't hold very high levels of oxygen once it gets above 25oC so you can suffocate the roots that way... thats why whales n shit live in colder waters cuz it holds more oxygen and can therefore sustain more/larger life ... just measure everything and take some pics man