[grim]

Hello everyone.
I have a 3g tank with just Ghoul in it (Betta male). The tank harbours (apart from the fish) gravel substrate, one live plant (Anubias nana), a piece of driftwood and a PVC cave. No filter whatsoever.

I bought a heater yesterday and set it to around 78. I left home for a few hours and when I came back the thermometer said the water was at about 83!

Now, what I was wondering is, could this be due to a faulty heater and/or thermostat, or does it get inaccurate readings because the water is not "moving" at all (lack of filter)?

(all this assuming that my thermometer is in good working order, I may grab another one just to be sure)

 

[callistra]

Heaters seldom to never hold actual temp. This is common and it's why it is imperative to have an in tank thermometer and adjust the heater -slowly- while you're around to monitor.

How is your fish? That was a quick high climb..

Usually you want to set the heater lower to what the tank temp is, then click up one degree slowly to when it gets on. That's how you know the difference in temp. From there click up 1 to 2 degrees per hour.

Also for something that small you don't want anything more than 25w.

 

[grim]

Thank you for your answer.
Just to be sure, I bought a new heater and a new thermometer (I needed them for another tank anyway).
I'll try your advice and see if I can make it work as it should.

The fish is fine as far as I can see. Trying the new heater now, seems to hold at 78-79.

I do have another question regarding the wattage. It's small so 25 is what you suggest, but what happens if I get a 50w in there (apart from more power consumption)? I mean, temperature is temperature, as long as it keeps it ok does the power consumpotion really have any impact on the tank?

 

[Geomancer]

Why not get a heater double the size needed for a house?

It's inefficient and un-even. Then, if it fails on, you'll be having fish for dinner...

A 50W can heat a 10 gallon, so you're over 3 times what's needed.

Temperature dials on heaters need to be 'calibrated' as they won't line up with reality more often than not. As suggested, set it real low, let it sit for awhile so the heater = tank temp. Then slowly raise the dial until it clicks on.

 

[grim]

I have a 25w in my 3g and a 50w in an 8g. Haven't found anything lower, so these will just have to do once I calibrate them.
Thank you everyone for clearing things up for me

 

[callistra]

Those are fine. My 5g have 50w. They're rated for 5 to 14g or so. In a 5g a 50w can heat about 15f above room.temp. in a 10g about 10f. If you let your house get very cold in winter your fish needs the higher wattage