I have three Softies ( 2 Eastern Spinies and 1 Smooth) in a 75 full of water with native fish. They have been in this setup for almost 6 months now and done great. I had them in a rubbermiad bin with a basking rock before but they never used it. I keep the water temp. around 72-74 degrees and they are active. Anywhere between 72- 78 degrees should be ideal.