Review on 🐠 AQQA Submersible Aquarium Heater: Advanced Quartz Glass Fish Tank Heater with Over Temperature Protection and External Temp Controller - Ideal for Freshwater and Saltwater Tanks! by Tom Loungee

After receiving and washing the heater, I put it in the tank and only after it was immersed did it turn on. I've always set it at 74F, last week it went up to 77F. The house is set at 71F and is not near baseboards or outside heaters. Tomorrow it will be 1 month old, tonight my thermometer reads 81°F on the other side of the tank (55 gallons). I immediately turned off and removed the heater. I grabbed a spare thermometer, it was also over 80°F. I removed the case to check for cracks and I can't see anything. I don't leave reviews but I hope to save someone else from blowing up a tank over this heater. My fish is doing well and I'm glad I caught it so early.