Help!! leaf edges curled down and droopy

Im fairly new to growing indoors, this is my second grow indoors and i'm having a bit of a problem. the leaves are curling down on the edges and the look really limp and droopy. also some purple streaking on the stems that kinda starting to spread to the leaf veins, and slight discoloration on the leafs. Now my plants were doing wonderful until two nights ago and the ONLY factors that i have changed is new "better" lighting (upgraded from shitty diy fluorescents to a t5 8 bulb fluorescent) and i started to PH my water with general hydros PH up/down, but literally only had to use like 1 or 2 drops in a gallon of my nutrient solution, which shouldn't affect anything. I had been using tap water without PHing it which i think might have caused a nutrient lockout. so i will start using RO water. I've been looking everywhere and cannot find one picture that look like mine do of any deficiencies. PLEASE HELP!!!!!

I am growing in 2.5 by 8 closet with 2 fans taking in fresh air and circulating the grow. Growing under a t5 8 bulb fluorescent. i have 4 clones in 1 gallon pots, and 5 seedlings in half gallon pots, all in happyfrog soil with added perlite. For Nutes im using fox farm's growBig with roots organics Bio Catalyst.
ANY HELP would be greatly appreciated !!!!!

I forgot to add that my room temps around 70 at low and 79 at high. and its not over or under watering .I dont have a humidity guage yet :/

come on people help a brother out!! is it cal/mag def.?

Get a humidity gauge. Also, it could be watering too frequently and compacting the roots (different than overwatering). Leaves drooping down is a sign of any combination of overwatering and/or too much humidity; take that w/ a grain of maple sugar.

thank you for the advice. i will definitely do that.