This is a repeat of another thread under discussion. The following is my opinion, from that discussion....
all you do need to do is get two small fans that will fit into the canopy, one in and one out.
The temperature fluctuating is not really a problem, the ocean may have very stable SG and PH levels but the temperature changes all the time in nature. 90 at a prolonged temp may (even experts are not sure) cause a problem. 82 - 86 is not so horrible.
Your creatures are most likely very happy right now. Most hobbyists keep the temps at 76-78 to slow everything down. It gives them time to fix algae blooms and the like, because the warmer temps allow things to grow much quicker.
The fish really like the higher heat, that's why when you have a sick fish it helps to raise the temperature, it eases stress and makes it more the way they like it, helping their immunity system.
I saw a TV program that showed the deep ocean with an underground volcano, the coral was beautiful...It was really HOT, they couldn't get to close while filming.