Curling tips

I have two blue dreams on the go at the moment in biobizz lightmix.
They are under around 800w of led light
Fed with biobizz nutes
Temps range from 25 with lights on but drop to around 18 lights off as it’s winter
In air pots (4gal)

. They have been very vigorous, but over the last week one has begun curling down at the tips. I suspected they are too close to the lights as they have shot up at the flip, but one is just as close but no curling. All other leaves are praying up aside from one plants main three heads at the top. I must admit I havnt checked run off ph as with biobizz I have never ever had a problem. I do feed with every watering so could this be the issue (although I have had no issues before) I usually feed bloom 2ml/l and fish mix or grow at 1ml/l but I work up to that amount to make sure I have no burn.

So could it be ?
Overfed
Temps too low at night
Too close to led lights

Seems to be too much nitrogen and from the looks of it, not enough light. You say 800 watts of led??? I see a small 125 watt cfl light bulb.

The rest are above the door. 2 x blurples probably 150w each at the wall. And 5 100w led corn lights.