Hello. It's staying unseasonably hot here this Summer. There's a pergola over my outdoor Goldfish/Koi trough. The water is staying a bit warmer, but I have some aeration going and I remove and replace quite a bit of water a couple of times a week. The large water changes increase the oxygen due the splashing as the tank fills and the new, treated incoming water is cooler than what's already in the tank. So, the oxygen level remains pretty high. The fish do enjoy a flush of clean, cool water twice a week.
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