Review on Submersible Energy Efficient Controller Thermostat Thermometer by Crystal Palmer

Unfortunately, one of the two tanks I ordered for my Betta aquariums had a suction cup that didn't hold up. They also heated my 2.5 gallon tanks to 80F so I turned them off but assuming it's July and it's over 75F outside and my room has been heating up for a day after I have them had installed. If you recommend using a suction cup glass thermometer in your tank to make sure it's not overheating, or at least only run it when your house is a little cooler. I like their basic look and the fact that they can be glued to the floor. And they certainly help keep your tank warm if you're having trouble keeping it warm. Again, keep an eye on your tank overheating.