Review on 🐠 Efficient FREESEA Aquarium Heater with Submersible Thermometer - Choose from 25/50/100/200/300 Watts! by Christina Magnus

UPDATE: I went to feed the fish today and saw the top of the heater was covered in a layer of slime or something? (see image) I'm not sure what it is or if it's supposed to be happening. I hope this doesn't cause the heater to malfunction. ORIGINAL REVIEW: So far so good. It took me a day and constant monitoring to finally get my betta and shrimp at the right temperature (24°C) in my 2.5 gallon aquarium. The available temperature options jump from 73 to 77. too warm (the temperature went up to 81 and kept going up). So I reset it to 73 but the temp dropped to 76. Finally, I ran it right between 73 and 77 and now the temp stays at around 78F. The water heater also comes with a suction thermometer. I used a ZooMed digital temperature sensor (which I use on my turtle) to make sure it's accurate. The difference was only 0.1. PRO: • adjustable • turns off automatically when set temperature is reached • light turns on when heater is on • comes with a free CON digital thermometer • doesn't have a built-in thermometer like my old kettle (supplied free , but takes time to save space, especially in a small tank). • Doesn't heat to set temperature (heats more) but luckily it's adjustable as it gets hotter than set and goes up to 95, I think 25 watts would be enough for 5 gallons.