75-80 F are good temps.

75-80F is a good range. For most fish I target 76F as a personal preference. That is just me, 74-82F are suitable for most FW tropicals.This is harder in these summer months, especially when the lights are on. I don't sweat it if it's not 76F, just what I consider ideal. I have found that the lower side of that to be helpful to plants. Lower temps also have more oxygen available. Higher temps will help speed fish metabolism, but this can make them slightly more aggressive. Maybe just competion for available food?

I agree and if you have a climate controlled environment in the house, I honestly don't think heaters are necessary at all.

Currently, our house is set at 76, so without the tank lights, that's as cold as the tanks can get at night, and the fish seem perfectly content to slow down to sleep, then be active in the warmer water and light of daytime, when the lights warm the tanks to a temp greater than the ambient air, and the temp change is gradual, morning, and night.

Which, if you think on it, is exactly how it works in nature.