New Problem - Help needed

I intentionally run my tank at about 81-82 degrees. Once you get past the 84 mark and creep past 86 is when if for more than a couple hours you will most likely see some losses.. SPS and LPS will most likely take the heat worse than softies though and since your tank is mostly softies it won't be as bad as a hit.

I would remove glass top if using one, shorten photoperiod if need be, raise fixture a little or even better get a couple 3.25" or better fans and have them run blowing across the water and the lamps.

Cranking the AC if possible is another option, and if all else fails and you are in a pinch start freezing gallons of water and float them in the sump or DT and let the melting of the jug cool the tank a bit. You can also do this with RO water and remove the cap of the jug so not only is it cooling it is topping off the tank.

Good luck all in warm climates!!