What is the best heater for a 2.5 gal tank

I'm looking for a small heater for a 2.5 betta gallon tank. I can't believe the wattage difference in all these minI heaters, anywhere from 5 to 50. I can't decide which one I feel comfortable using. I would like it to be adjustable since its for a betta but also submersible because of the small tank size. Is there such a thing in a small heater? Any input would be great.

 

Aqueon 10w is for up to 5 gallons. I would seriously consider getting the betta 5 gallon at minimum. 2.5g is still too small due to rapidly changing parameters and temps.

 

This isn't my tank. It belongs to my mother and she doesn't have space for a 5 gallon. I picked it up from her to get it set up and cycled. So I've got to figure out the best heater for this tank.

 

I use the Tetra HT10. It's a 50w preset (78° +/- 2) but they do keep my two 2.5's a constant 78° F with no fluctuations.

People also recommend 5 watts per gallon with an adjustable temperature setting. So a 10-20 watt with an adjustable setting would be reasonable too. I think Marineland has a couple choices there.

 

I have a HT10 sitting around. I was just thinking about that one today. Maybe I'll throw that in there and test it out for a bit

 

People have pretty mixed reviews on them on how effective they are in the tank.

How old is the heater? If it's over 2 years or getting close, I'd suggest a newer one.

The biggest pain to the smaller tank is getting the water change temp to match

 

I've used the HT10 with good results but I would be careful with it because there have been reports of problems.

 

People have pretty mixed reviews on them on how effective they are in the tank.

How old is the heater? If it's over 2 years or getting close, I'd suggest a newer one.

The biggest pain to the smaller tank is getting the water change temp to match

I have only had it a couple months. Just don't really need it. I always add exact temp water back to the tank. I'll be sure I go over all of that with my mother when I return the tank.

I've used the HT10 with good results but I would be careful with it because there have been reports of problems.

Do you know what kind of problems have been reported?

 

IIRC, the complaints were mostly of two kinds. Either the heater thermostat didn't maintain the advertised temperature but continued heating, or the glass tube cracked while in the tank. Come to think of it that latter complaint could have been related to the former.

 

IIRC, the complaints were mostly of two kinds. Either the heater thermostat didn't maintain the advertised temperature but continued heating, or the glass tube cracked while in the tank. Come to think of it that latter complaint could have been related to the former.

The only other complaint I know of is that the unit doesn't work at all, either no light or constant green without heating.

Just make sure the heater is off during the water change and you should be fine if the unit works properly.

Is her tap water "fish safe"? I wind up having to float my bucket in hot water because I need to use distilled/reverse osmosis, whichever I find at the store.