Problem with heater, tank water too hot advice Needed.

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Problem with heater, tank water too hot advice Needed.

Postby teddybear154 » Sun Aug 17, 2014 4:19 pm

I have a 200 ltr fish tank. In the tank I have 6 neon tetras, 6 flame tetras, a pearl gourami, a angle fish and a pleco.
The heater I had broke so I had to buy another one. The heater I bought was a Fluval E200 it's the type with a digital display. I followed the instructions and put heater in tank and left for about 1 hour before plugging in.

I then plugged in and left abit longer. Then I set the temperature to 26c which was temperature tank was already. I checked back abit later and discovered tank temperature had gone up to 29c.I double checked heater and it was definitely set to 26c.I turned heater down a bit. But it made no difference. I have slowly been turning down the temperature. Heat is now set a 24c but tank water is at 28c.

I just don't understand it. Room where it is is not that hot, the weather is not hot where I live at the moment. I have another tank in same Room next to this tank that reads a steady 26c.

Could the heater be faulty.

The only other thing I should mention is that I am currently running 2 external canister filters at the moment as origonal filter started to fail the same time as heater. I thought it was probably best leave old one running whilst the new one builds up its bacteria etc. new filter has built in uv. You can turn the uv off though. I have been running the uv some of the time but not all the time. Is it ok to run both filters for a while.

Could running both filters or the uv be causing the water to get or stay so warm.

Will the fish I have in tank be able to cope with temperature so high for a bit or could it harm them. All fish seem fine at the moment.

I have checked water temperature with 2 different thermometers and my seneye device.

Any advice much appreciated.

Thanks in advance
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Joined: Tue Jan 14, 2014 7:47 pm

Re: Problem with heater, tank water too hot advice Needed.

Postby Rockfish » Sun Aug 17, 2014 10:25 pm


It's definitely a good idea to run both filters in parallel until the new one is sufficiently mature. I don't think running both filters and the UV would add a noticeable heat difference to the tank.

If your thermometers plus the Seneye are giving you an accurate temperature, then at 29'C it shouldn't be too much of an issue as long as the water is clean and well-oxygenated, which it should be if you are running two filters. I had tanks in my fish room running at 30-32'C during the recent hot weather in the UK, and it didn't cause any issues, even with some species that prefer it on the cooler end of tropical.

One thing I would say about the Fluval E heaters is that they do seem to need a decent flow around them to function properly (as do any heaters really). The plastic guard around them does make the flow more important. With two filters you should have decent flow as long as the heater isn't tucked away in a corner behind décor or anything.

It could be that the heater is faulty. It's one of the few on the market with a built-in thermometer - does the reading on the heater agree with your thermometers and Seneye device? Is the heater flashing a warning, as those Fluval E heaters are designed to do if it varies from the set temperature?

Remember there's lots of info at The Tropical Tank main site!
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