I like the pool to be around 83 - 85 degrees. Some people like it quite a bit warmer, but in my opinion, if it gets too warm, it is no longer refreshing. 70 is way too cold for me! Solar covers really do help. Without one, each night you lose a lot of the heat that you gain during the day. They are a bit of a pain to deal with but definitely make a big difference. I resisted buying one for a few years because I didn't want to mess with it, but after I did buy one, I saw what a big difference they make.