I agree with Headshake...but...I'd follow the instructions on the bottle rather than skipping around, too. Advanced Nutrients are specifically formulated (so they say) for cannabis, so dicking around with their rates and schedule (or not following a schedule) can have negative results.

Takes forever for 5 gallon buckets (about what...8 dry gallons...?) to dry. Are you watering too much or too often? Cannabis prefers a wet-dry cycle. Do you have air vents drilled into the sides to prevent stagnant conditions?

You can search for the low stress twisty-tie training thread for the height issue. (LSTTT)

I'm running two 400w hps's in a 10 x 12 outdoor shed that's 96 degrees ambient right now. No cool tube. You'd be surprised what these ladies can thrive through.

(shown with optional heat shield)