if you are overwatering, you should know... if not, try moving lights further away?
2 of those lights is a ton of umol/s... i'm 90% certain it's your lights.
if in vege, go down to 16 hours, that will help. you are torching them with light. in bloom with only 12 hours, you won't have to be as careful with them. may need them further away in vege too.
do those have an adjustment for brightness? that'll work too. a cheap lus meter or a nice par meter can help you dial it in. find a measurement it stays praying most of the day.
like i said, you'll be able to torch them in bloom due to less hours.