Review on 💧 Efficient and Reliable ViaAqua 50-Watt Quartz Glass Submersible Heater with Built-In Thermostat by Cynthia Taylor

that's planted for my 5 gallon. So far it seems to be working fine. No leaking capsule, no overheating or temperature fluctuations. I only set it at 79F and it kept the water at 80F. My room is about 67F so it heats up just fine. As a tip, let the heater sit at room temperature for a while, then install the heater in the tank and let it adjust to the water temperature for an hour before plugging it in. This reduces the likelihood of cracks and condensation. The lid, which you can find here on Amazon, is also a great addition, especially if you have delicate fish or plants that you don't want to get too close to.