Hi,
Constant 90 is way too high... Fans will help cool things down..I also noticed when I do water changes that the temp drops. The reason is the waterfall effect my pumps make, I don't disconnect them until they are about to be exposed to air. So you could remove some water and let the water drop dump back into the tank. It ill make salt creep real bad but it will lower the temp 7 to 8 degrees, even more with a fan running.