You might be running the pumps too long and too often
I do mine 4x a day and for 15 min. It takes about 10m for it to drain, That equals almost 30 hr of water up.
as for the light. Keep the top canopy an even 78ish degrees and use the light distance to get that temp. The closer you can get that light to em, the better. (obviously without going over 80 degrees)
I dont own a mega garden either, figure ill try and help thou.