I am growing in a coco/perlite mix in 3gal containers under 600watt HPS lights.
I am using AN nutes at the following levels Micro(5-0-1)@4mL/gal, Grow(2-1-6)@4mL/gal, and Bloom(0-5-4)@4mL/gal and a Cal/Mg Supplement(2-0-0)@1mL/gal. My water is pHed around 5.8-6.0, right before I add nutes and I always check after adding nutes to be safe and it remains constant. I usually water when the pots feels light.
I recently bought a dehumidifier, thinking that if it were mold/fungus, it would slow the pread. With the dehumidifier, my humidity hovers right around 40%-50%, with temps usually ranging from 75-85 degrees.
Let me know if you need any more information then what I provided.
Thanks!