Review on Marina Submersible Aquarium Heater Watt by Alyssa Grinager

Using a 200 watt version in a 45 gallon sealed tank. As many have noted, the temperature scale is not accurate, so I didn't expect to get the exact temperature through trial and error. What I didn't expect was drift or balance time. My goal is to keep the water temperature at 79-80°. I set this to 79 degrees which resulted in my tank reaching 76.5° after 24 hours. After several days of trial and error and setting the dial at 83°, the water temperature reached 79.5°. But for some reason the water rose about 0.5° per week. When it reached 81°, I spent several days reducing it bit by bit. By the time I set the dial to 81.5, I raised the temperature to 79.5, stayed there for another week, and then slowly dropped to 77. Almost 2 months later I officially give up, I installed my Tetra 150 watt heater, this heater is set to 78°, my temperature stays between 77.5° and 78°. I only check the temp 2-3 times a day, maybe this jetty heater fluctuates like crazy during the day, I've never had a heater fluctuate that much (including the cheap no brand stove this heater replaced)