Leaves curling down! Please help!!

So there seems to be an issue with this plant.The leaves have started to curl downward and inward. I'm trying to narrow down the problem as quickly as possible, so she will continue to thrive! She is 3 weeks into flower, and was looking wonderful until a couple days ago. Temps are perfect. Humidity could be higher, but still good. Keep in mind, it's night time, so she is a little sleepy. But you will notice the curl in the pics. Here's the setup again...

1000W air-cooled over a 4x4 tray
Flood and drain with hydroton
GH expert food regimen with RO water

Once again, any advice would be great. Thanks!

-Rock

To me that looks like the beginning stages of nute burn...

you havent said anything about ph levels? that could help!

didnt just use neem or insecticidal soap did you

looks like nute lock and / or your ph is way off. flush flush flush