Mine hit 90 yesterday for the first time. Pump running 21/7 low speed for one turn over a day then 2-4 hours at rpm for two turnovers a day rate to run vac cleaner. We've just started 100 F days, a few days ago, with nights still dipping into high 70's, but that won't last for much longer. Right now losing about 3 F at night. In a few weeks we'll be lucky to get below 90, air temps, at night. I may have to put a fountain in, to run at night, to try to lower the temps down for rest of summer.
I'm putting in 1/2"-1" a day of cooler water to replace evaporation (sun and wind) and splash-out.
gg=alice