Review on Submersible Energy Efficient Controller Thermostat Thermometer by Molly Kaye

I have had about 7 aquarium heaters in the last 4 years. Unfortunately, this one looks like another mediocre heater. It's better than others, I like the thin hard case. The problem with these (as with others) is that they just don't control the temperature accurately. I used it in a 3 gallon pico reef aquarium and now use it in a 1.5 gallon betta aquarium. I had to turn it off several times as it turns on even at temperatures above 83 degrees (see image). This heater tends to fail on the high side at 80-83 degrees, with an ambient temperature of 74. You really should set it at 78 degrees, with 80 being the max. As far as I can tell it works best in still water and gets hotter when water is circulated with a pump. It's a bit ridiculous, but I need to hook it up to a temperature controller to regulate it better and give me peace of mind. By comparison, I could buy another 50w Cobalt Neo-Therm for about five times the price and never worry again, but I keep buying cheap heaters like this in the hope that maybe the company is right this time . I mean indeed stability is key when it comes to our aquariums. The error should be smaller and the error on the colder side.