Review on YukiHalu Mini Submersible Aquarium Heater With Thermometer And Temperature Controller - 25W, 50W, 100W, Or 200W Options For 5-40 Gallon Fish Tanks by Jon Odom

Arrived on time. Set up in a spare "tester" bowl before using in with the fish. Like the digital readout and easy to use temp settings. Heated up the water relatively quickly, although it always read about two degrees off what my two probe thermometers were reading. Could have adjusted for that, but the unit would get up to the set temp, light turn green, go a few tenths (according to the readout) higher, and then stop heating. Red light would come on, display just dropped off a tenth of a degree at a time until it was several degrees cooler than the set temp. Did that when I gently swirled the water around, did it when I did not. I can't have my betta having wild temperature variations like that. Would have liked to have discussed with the seller, but is shipped by Best Buy (?) so their bot won't allow me to do so. Really wanted to like this little unit though - it's a good size for a small tank. No alternative but to send back for a refund.