Review on 🐠 VIVOSUN Aquarium Heater: Submersible Titanium Fish Tank Heaters with Intelligent LED Display and External Controller by Vettee Welch

When I first received this heater I placed it in my aquarium as per the instructions, fully submerged in water. I plugged it in and it started blinking E1. It was a bad sign. The instructions don't say what to do, just that E1 means "If the metal temperature sensor was in the air, the product will show error code 'E1' and 'E1: Lack of water or incorrect installation'." I thought I had Bought crap but I decided to set the temp and see what happens. Good thing I did, because the temperature in the tank was steadily rising. The whole time the heater was flashing with temperature and then E1 with a red light. until temperature the display changed to blue and the error code E1 disappeared. My Oscar is now happy that his water is warm again (his old heater broke) and the heater works great. If this heater lasts even a year I wouldn't hesitate to buy another one.