Wow 90 is max! Cover and lites off with a fan blowing air on the water line maybe even 2. Also point ur outakes or powerheads at the top so there's surface aggitation! Also more bubbles will help too, just make sure u don't put freezing water in and temp shock him! I have a fan under my stand and a circulator 3 inches below my water line and it blasts water up, these two methods help 4-5 degrees
Go S. Vettel #1 rb8
No you said 90 was max.