Bought this from petco. Thought was a nice well constructed water heater. Especially because it had the plastic housing to protect fish from burns. I know it can be useful since they can get pretty hot to touch in smaller tanks.

I use this in a 3 gallon tank when quarantining new fish. The temperature is completely unreliable. A couple times i used it stayed at 76 which is what I set. But I would say 95% of the time it doesn't have the right temperature. It always is higher than what I set. Recently it rose to 87 degrees overnight. Had to do water change to lower temp. I adjust the dial to 68 degrees and it is still on. I have to adjust to lowest for it to turn off and turning back up doesn't even turn it back on when it passes current temperature.

Setting it to a 68 doesn't mean it will heat it to 78deg, it could just not turn on and your fish will get cold.

Basically this is completely unreliable unless I got a lemon. Only good for keeping your tank to within +10to 15 degrees.