The Intex $15 fountain from Walmart is pretty to look at in the dark. But I accidently left it running overnight and our water dropped to 72 degrees. Brrr… We are in the middle of the Arizona desert and it was 99 degrees yesterday. And our pool is in full sun all day. By 4 pm the water was still only 77 degrees. I love a brisk cool off, but that’s a little too cold!