Oops, froze the fish! Heater advice needed

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Aquarium Advice Apprentice
Jan 10, 2006
Connecticut USA
We've had our Eclipse 6 gal tank for almost 2 months now. We have a platy and a tetra and 8 baby mollies. It's cycled and overall doing well. We are doing 35% PWC's weekly. The heater is a basic 50 W submersible with a dial on top.
We went away for the weekend, turned the house temp from the usual 70 down to about 62 degrees. Also left the light off since we don't have a timer yet. When we got back lastnight, the platy was sluggish and the water temp had dropped to 70! Now that we have the house temp back to 70, the water has come back up to 74 (so far) and the fish are getting back to normal.
Is there a better kind of heater with a thermostat that would fit our tank that would be able to keep the water temp more accurate despite the drop in the house temp? We don't go away often in the winter, but we'd prefer not to have to heat the whole house just for the fishies! Thanx
I have personal preferances to Won Brothers (no 50W heaters unfortunately), Ebo Jäger, and then Tronic heaters. I believe that Tronic will have a 25W heater (better size for you) and the cool thing about them is that they can be encased in a seperately purchased cage for a lack of a better word.
I decided to go with the Visi-Therm 50 W from Big Al's Online. It sounds like it will be way better than the heater we have and should probably be able to keep from overheating the water in the summer too. Thanks so much everyone. This site is great!
We've had the Visi-Therm 50W in the tank for about a week now. I set it for 77 degrees and it's brought the temp up to a steady reading of 80 degrees on our thermometer. The fish are doing fine. I remember reading somewhere that the thermometers can be inaccurate, so for now I'm thinking that I should believe the Visi-Therm and assume that our thermometer reads high. Would you agree?
If you're using a stick on thermometer, you are correct that these can be inaccurate. You might want to consider getting one of the thermometers that float in the tank or a digital thermometer. These tend to be more accurate. Heaters can be off by a few degrees, so it a good idea to try to locate a more accurate thermometer. This way you're also more likely to catch it sooner if your heater starts having problems (either stuck on or off).
even a visi-therm thermostat isn't perfectly accurate, consistent, but not accurate. get an internal digital thermometer..they are about as accurate as you can get for cheap.
What we have is a mercury thermometer suctioned to the inner wall of the tank in the corner opposite the heater and filter. I will look into getting a digital one. Thanks
I like BigAls too, but DrsFosterandSmith.com is having a sale on the Visi-Therm Stealth's right now . . . I'd check that out quick before you place the BigAls order. Only a couple of bucks difference, but for some of us, that means a lot.
If you're thermometer is truly a mercury one (silver liquid), you may want to get it out of the tank now instead of waiting for the replacement. An accidental bump during a water change could break it poisoning your fish and risking your health as well.
I have a Visitherm Deluxe in my 75, no complaints at all, and adjusting the temp is easy. However according to the dial it's 77, the actual temp is @ 79. Not too far off..

I use a thermometer (alcohol) to get the reading and adjust it by that. but once it's set, you never have to touch it again.
It's not a mercury thermometer...my mistake.
It sounds like for now I should trust the thermometer a bit more and turn the heater down a notch. Thanks all.
i just wanted to say i agree on the digital thermometers... i just bought 4 of them.. 1 for each tank and one for each snake tank. Its really nice to see the exact temp all the time.
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