Hi all. I'm quite new to the aquarium hobby so I'm looking for some advice. I've got an oase adjustable heater. When I was fishless cycling the tank it was set at 30 degrees and didn't vary too much. Now I have fish I want to keep the temp at 26. I've set the heater to 26 degrees but my track seems to be sticking around 27 quite steadily. ( betweem 27 and 27.3) So I dropped it down to 25 and it still seems to be sticking around that temperature. I did turn the heater off for a while and my temp dropped down to 25 over night. When i turned the heater bank on it went back up. My room temperate is variable but around 23-25 degrees. My question is, is this normal? Does anyone else have an oase filter which does this? Are there any visible signs I can look out for of a damaged heater?