600w light

So Im doing an hydro setup for the first time... My ladies are still seedling so I jave them under 2 (2FT) T5s HO UNTIL I move them into my cabinet with 600W MH. In rest are a little older. Why is the are the coloylodon leaves turning yellow... The new growth looks mangled as well... Is...

I have 2 600w not air-cooled. In a 4x8. I can't find any posts apart from 2 tents one fan. I just wanted to know as I have 2 and whether it'll be too strong and curve my tent walls in or it'll be just right. Cheers Happy blazing