the plants are curling even more!

just trying to narrow it down for diagnosis:

ive raised the humidity level up to 85% with the cups of water between plants, so it wasnt the low humidity causing it...

ph should be well back up after a week of watering with fertz at a ph of 7.0/7.5...

they look a good shade of green, and no new yellowing, so its not a deficiency or over fertalizing...


only things that i havent got perfect i know of:

water is tap water not left to sit out.
air is only circulated once or twice a day.
temperature probably drops quite a bit overnight.

ive just put in a heater with a thermostat and also thermometer that records the highest an lowest temps today so it'll switch on if the temps drop overnight and will be recorded for me.
I wouldnt of thought the chlorine in the water would be that damaging, i got the impression it only made a grow slightly better, would u say it makes much difference?

maybe eventually i'll try to wire up the fan to a dimmer switch so its always on and running low, but its not likely for a good while to be honest,

any helps much appreciated!