Review on Cobalt Aquatics 31020 5W Mini-Therm Aquarium Heater - White/Black, Energy-Saving Mini-Therm Heater, 5 Watt by Deshaun Fisher

My 1.5 gallon tank started in 60 degrees in the morning. I put in a household lightbulb and heated it up to 72 indoors. All day long alone I raised the temperature to 68 degrees. A 5w heater arrived and I followed the instructions. I called the service number for instructions to make sure it had to be dipped under the cable. You are the service department. replied immediately and gave me instructions. They were nice and helped immediately. The line is below the waterline. After the heater had been in the pool for 20 minutes without a mains connection, I switched it on. It took a long time to heat up to 72 degrees. At first I was worried but the next morning I checked the temp and it stayed at 72 degrees and there was condensate on the top of the tank. It works great so my Betta doesn't experience sudden temperature changes at night when it's 15 degrees outside and 66 degrees inside. It's been a few days now and the temp is consistently 72. Love the heater.