Early veg curling leaves | claw |1st time grower

Hi Forum
I have 6 plants - 3 x 6 weeks and 3 x 4 weeks.(at back of grow area in pictures)
Been feeding every 2nd feed which is around 2-3 days. as I am a first timer I have never checked EC but bought me a tester and found horrible EC values when I flushed the plants. range 2-5 3.3 I flushed twice on all 3 plants that are 6 weeks in and overnight suddenly all leaves seems taco dark green and the tips pointed down at 90 degrees. i used to have 1 x 120W led panel and have swapped out to 600W HPS light. the curling started before the changed in lights … i have the lights fairly high from canopy around 30". and he 3 younger plants do not show curling and seem happy.

I read the EC values are not what they should be ,

growing in perlite soil in 7 lire pots
temps are high around 29 during day and 27 at night.
think need to add AC

not sure what to do … wait and let the 3 with the claw dry out and start nuts again ?

Pictures will help alot, with a better diagnosis.

Happy Growing :vulcan_salute:

just uploaded … i have now just bought nutrients from a company called yieldtech.
these 3 curling leaf plants have not drunk the new nuts … could it be the old nutrients that is causing the block …

It could be nute lock