Review on Hygger 200W Digital Quartz Aquarium Heater with External LED Display - Auto Submersible Heater for 15-30 Gallon Fish Tanks by Donna Armstrong

The heating generally suits me. I had limited space where to install it and it was very compact. The suction cups keep coming off but it doesn't float to the top and since I have it on my back pump it doesn't cause any problems. The temperature control on the controller isn't the most accurate either. It's close, but I've noticed that it can read a little high at times and low at other times. I think it just has to do with it only reading to an integer, not a decimal. I saw 78.8 degrees in the tank and the controller reads 80, so it's not just a rounding issue. However, it was always within 1-2 degrees of the actual temperature. Still, it's a decent temperature controller with a nice little heating element if you need one for a small space and don't need to maintain a really constant temperature and can't fluctuate a few degrees.