I keep mine at 78. 70-80s is fine. Higher temps need some good water movement. They do fine with tropical temps. Fine with ph as long as it’s not swinging. Can range from 6.5 to 9.
Yes 75 is good. I keep my fish room at 78 and the tanks are usually at 76 and the pond (where the polys are) is usually around 73. Mine are happy and healthy. Very active too.