Droopy girls

I have 6 autopots with coco natural, pepples with air pump.2x 47litre butts feeding them. I'm using canna feed. E.c. 1.6-18, p.h 7.0. 5'inch inlet, 6'inch outlet, temp is 50'f/84'f off/on. Humidity 45/55 on/off. Room size is w1300xd1600xh2000. With 3x 600w. O.k. Basicllly I'm 6 days In to flowering 12/12 staggered 18/6 last week, things seemed fine until then, know they look really sad even droopy when light is on, plus some tips of some leafs of gone yellow. I'll get some pics on later.
PLEASE HELP ME!!!!!

Your liquid pH readings shouldn't go above 6.

34 degree temperature swings are an issue. Try to keep that at more like 60 off and 80 on... even that is pretty extreme. If you could keep it at 76 on and 70 off you'd have much better results. Keeping the root zone warm can be an issue in wet coco.

cheers fella's for the reply...hear r some pics.

snow crash turned 1x 600w light off to lower temp, know reads 75/ on, but also installed a fan heater for when lights r off and set it to be around 60.

m/finest p.h tester is playin up but im on a mission to get that sorted today.

i also added some new top soil to each plant. reason being i noticed that each one had like a white salt look about it?!.then watered slighty.

anymore advise wud be appricated.

just a quick update.....

all is well lowered nutes and p.h.=1.6/6.0.

think temp was a big effect.