[VinceIII]

What do you suggest for a tube-style 25W heater for a 5.5g aquarium? This might sound silly, but I want a tube because my betta likes sleeping behind the current heater on the top suction cup. As much as I like the Cobalt Neo-Therm, it doesn't look like it has enough space for him to do that.

Here are the models I've found that look good:

Jager - I would have already ordered one, but have read that their quality has gone down recently. Also, some people apparently have difficulty calibrating it. What do you think?

Cobalt Accu-Therm - Cobalt seems to have a good reputation (aside from some defective larger Neo-Therms a while back), but I don't see much feedback on the Accu-Therm.

Hydor Theo - It seems like a popular budget choice, but I get the impression that it isn't quite the quality of the other two.

I'm replacing the current heater, a Pet Supplies Plus model, because white slime has started accumulating on the rubber end pieces. I did my best to clean it off, but it came back within a couple of days. The slime isn't anywhere else, so I think it's just this material.

 

[Nordic]

It will go away after some time... just wash it regularly for now.
Your new heater will do the same thing..

 

[VinceIII]

Okay, I'll I continue washing it. By the way, I was wrong about the heater ends being the only place where the white slime is. It's also on the suction cup holding my thermometer. Do you know what the white slime is?

Although I'll continue with this heater, I should still look at options for a backup heater. So to the original question, what do you think of the three heaters I asked about? Are there any other 25W options I'm missing?

 

[Bobioden]

I have 2 of the Hydor Theo 25w for my 2.5g. One in the tank, and the other for back-up. They are very nice heaters. Easy to calibrate, and small footprint.

 

[VinceIII]

Thanks for the info about your Hydor heaters. It looks like the top is hard plastic, so it shouldn't have the white slime that seems common on these rubbery parts. My plastic filter is right next to the heater and doesn't have any slime on it.

After doing some more googling, I might replace it if I find a model without the rubbery material at the LFS I'm going to today. The current heater is still in the return period, and they said they'd take it back.

 

[Nordic]

Some rubbers are just very prone to doing that. No idea why though, but I think almost everyone encounters the snotty rubber situation in new tanks.
Also happens to some types of air tube.