As an MH user I have found no need for a heater. My tank seems to do well with the temp swings in the evening. The "swing" is only a couple degrees....3 is the highest I have seen. This is the 8th tank I have ran like this. No heater has been owned for the past 6 years. To avoid confusion, started with a 12g and upgraded multiple times moving livestock over and over which we all know they love to do. Heat has never been an issue, chilling water was an issue for one season but now that too is no longer a problem. $10 fix to chill water