Review on BOEESPAT Submersible Aquarium Heater 100W/200W/300W/500W with Anti Scald Protector, Thermometer Included - Ideal for Marine Saltwater and Freshwater Fish Tanks by Brittany Lawrence

Pretty decent heater for the price. It would be a bit warmer, or I could just leave the windows open so my room is 55 degrees. But in any case it works very well. If you keep the room fairly cold like me, you can turn it all the way on. My maximum temperature was 76, even though I was losing a lot of heat to the bubble filter. The heaters are not to blame. This will work much more efficiently in a warmer environment, but hey. The fact that it works so well for me given the strain I put on it means that if used correctly it will work amazingly for you. Will definitely buy again as long as everything is as it is now.