Adjustable heaters for nano tanks?


Currently, I use Tetra heaters in my betta tanks. I’ve had these for awhile with no issues, one of them for a year now and it’s fine. However, these are non-adjustable. On top of that, they aren’t keeping my tanks warm enough. They’re almost always under 75F (or around 21-24C). This isn’t warm enough for bettas. Both heaters are 50 watts, one is in a 5 gal and the other in a 3 gal. Even in the 3 gal the temp isn’t that warm, with a 50 watt heater. These just aren’t doing the job properly.
The one thing I like about these though, is that they are small in size. I’ve searched and searched, and I can’t seem to find any heater that is both small and reliable. I would go ahead and get some more Eheim heaters, but those things are HUGE. I tried fitting one in a 5 gallon before and it didn’t work. Not to mention I think they would be too hot.
I’m not sure what other reliable brands there are. I’m looking on amazon currently, but can’t seem to find anything with good ratings.
Again, looking for something that is small but also has adjustable temp settings.
Anyone know of any good ones?


I have 50 watt adjustable heaters from Aqueon in my betta tanks, but the heater itself isn't exactly small. I used to have a 50 watt preset aqueon that was pretty small and kept a 10g tank at 77-78 for 2 years before i put the adjustable one in there. I haven't had great luck with the Tetra preset myself keeping things above about 76.


I have been satisfied with both size and operation with heaters. Both the 25 and 50 watt heaters are 7.5 inches long so not overly big. I have also been satisfied with the service I've gotten from this ebay seller. I've only had to use their customer service one time and was satisfied with the resolution.
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