Hello! As some of you may know, we're preparing for a betta in a 10 gallon tank. We bought a Hydor minI heater for a 5-10 gallon, only to later find out that it's not adjustable. It says it keeps the temperature about 4 degrees warmer than the ambient temperature, but in our place we use the A/C a lot, so it's not very warm to begin with. None of the adjustable filters are made for such a small tank, and theyr'e also really expensive. I know all of the good betta owners on here must have some recommendation! Does anyone else have this heater? What has your experience been with it, and is it a good choice? Thanks!