Fan leaves Question

My fan leaves are starting to curl a little.

They have good color but seem to have a look of shrinking and the tips are culing down a little and even culing in the long way.

My ppm is 1200 and my ph is 6.1.
water temp is 68
night time temps get to 60-65
day time temp to 70-75
humidity is low 20-30%
my drip sched is 15 on every 1-2 hour

I had a small fungas gnat prob that i resolved with a small drench of Azamax.

I hope these pics help.

I would say that your plants appear to have a bit of heat stress. Heat stress looks similar to nitrogen burn and the tip start to curl downward. Though your room temperature readings appears to be normal, the temperature of the leaves may be too hot or dry. Your humidity level is way too dry. When air is dry, the plant becomes less tolerant to heat stress. Your plants are fairly small, so you should try to get your humidity around 50%-60%. The smaller the plant, the more humidity is necessary. Clones: 80%-100%; Veg: 50%-60%; Bloom: 40-50%; Last Week: <40%. Very low humidity is great for the last week of flowering because the plant is essentially dying off and the plant tries to preserve its fruits (or buds) by producing oily THC to keep water from evaporating out.

PPMs are way too high for plants of that size. I'll bet you're overfeeding them.

They dont show any signs of nute burn though.