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HELP with heating issues

926 Views 11 Replies 10 Participants Last post by  caribbeanguy
Ok. I'm still in the reefing game for now. :D

I have a 29 gallon tank with a 20 gallon sump that is about half filled. Total water volume might be 40-45 gallons.

I have been having SERIOUS heating issues. The tank can get up to 95 degrees during the day (like yesterday). The house has A/C and is around 75-78 degrees. The tank is actually sitting right next to a vent as well. So I don't know why the tank is so high.

Also, the sump is behind a wall that is the top of the stairs which leads to the basement. It is usually a little cooler at the stair landing as well.

Lighting is just power compact for now and not even an 8 hour photoperiod.

While the animals have been looking "okay", I want the temp down to around 78-80 at most.

As of this morning, I am floating gallon jugs of icewater. So we'll see how that does. House thermostat is reading 75 degrees, but the tank is reading 92.

I haven't had a heater in the tank since the beginning of summer. Other things running would be euroreef skimmer and mag 7.

Any other suggestions would be greatly appreciated!
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Does the water feel really warm to the touch? Are you sure your thermo is reading right? Can you put a fan blowing on the sump?
Maybe a pump is going bad or something.
Is your canopy enclosed? I thought pc's didnt heat the tank as much.
Wow, That seems pretty warm to me. With the use of a small fan blowing on the water I have been able to keep my tank at a steady 80 degrees. This may work for you as well. Be prepared for big time evaporation.

You said that the sump is behind a wall, is it a small area that the sump is in? If so, the small area might be trapping humidity from the sump and causing a rise in temperature in that area and the sump.

That mag 7 will raise the temp quite a bit, with that small of a water volume, if it's submersed in the water. That's a likely cause.

I agree witha fan on the sump, it'll help alot. $5-$8, depending on what store you go to, for a 8" clamp-on fan.
I agree, check the thermometer. Is this something that just happened or have you had this problem all summer?

78 in the house and 95 in the tank w/o a heater seems strange.

How's the flow from the Mag? Has is gotten weaker? I've had Mag's chow impellers and then they don't pump as much water, causing more heat. Maby take it appart and check it/clean the impeller.
What is the temp behind the wall? I had to take the doors off my stand for the summer and leave it open it was trapping to much heat even theough the back is open.

How are you doing? How is the baby doing?

Also in regards to the mag pump. Do you have it throttle back by using a gate valve to control the flow in the tank? If you do, that would be the problem.
my first thought would be the thermometer has gone bad. especially if everything in the tank looks like it doesn't mind the current temp. if it is accurate, I would check the Mag. It can put off some heat but I wouldn't think it would be that drastic. I would give it a good servicing to make sure it is operating properly. The only other thing I could think of is direct sunlight. Direct sunlight, even in a cool house, can produce a lot of localized heat. The thermostat on your AC will only detect the temp in the room that it is in. so it is quite possible that the room that your tank is in is much hotter than the thermostat reads.
Well, after I posted today, I decided to check the temp with a digital food grade thermometer. It read 74.8 while the one in my tank was reading about 92.

Then I tried the glass type temp/hydrometer combo. I know those are not very accurate, but that one came up just over 74 degrees too.

So my suspicion is that the digital one in my tank has become faulty somehow. I am going to test it by taking out the probe, and submerging it in a glass full of icewater. It should read around 32 degrees. If it doesn't, then I'll know it the probe.

I've had this heat issue since the first hot day of spring, maybe since around May. So far I've lost my purple firefish, but that was last month.

Mag 7 is submerged, but open all the way. Tank is not in any sort of sunlight what-so-ever. Sump is a 20 gallon high and completely open at the top. Tank is also pretty much open except for two thin pieces of glass that help to hold the light from falling into the tank...no canopy.

I will definately buy a clip on fan to try. Even with unheated water directly from the r/o in the basement, it's not enough to budge the temp.

I will try the icewater check soon!

Thanks for all your helpful suggestions.
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I had the same issue with my cheap digital thermometer. Here's how I fixed it. The probe end is just a thermistor. When the resistance across the thermistor goes down, the reading goes up. Mine had a tiny little leak in it that let saltwater in. Since saltwater is an excellent conductor of electricity, the resistance went down, etc. I dried it out and after the therm. read correctly again, I just blobbed CA glue on the probe to seal it. Been working perfectly ever since. Try it!


edit: it=is
Well, I did the testing with the icewater. The digital food thermometer went down to 32.5 degrees. The tank thermo stayed at 54.8 degrees in the same cup at the same time. So that explains ALOT.

I guess I'll be looking for a new thermometer.

Ironically, I've been told that the strips you use to place on the outside of the tank are not very accurate. Even at that rate, the strip is around 78-80 and the house is 77 right now. So that is just about on target and I am glad it is a faulty sensor and NOT my negligence for the water quality.
Good to see you back in reefing Skyler. We have to talk again some time.
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