Heaters, Themometers and temps -Oh My

[Meric]

Ok,

So I have a minor temperature issue and I'm not sure what's going on. I'm almost convinced the laws of physics no longer apply in my house.

I keep my house between 72.0 - 78.0 degrees, but my tank is always over 80 degrees. When the tank lights are on the temp rises to 86 degrees.

I have no lids on my tank, and 2 fans blowing on the tank, but the temps never drop.

I checked my heater and I cannot explain this, but the heater is set to 75 degrees via the knob, however it keeps my tank at 81 degrees. At first I thought it was my therometer that was off, but I have used 3 different thermometers all showing 81 degrees in the tank with the lights off, after it has cooled. One thermometer is a digital one. So either I have entered the Twilight Zone and all my thermometers have conspired against me or the temperature setting on these heaters are usless.

I only have PC lights (400 Watts) but it heats my tank up way too much, and the temps take all night to drop back to 81 degrees. Is there anything I can do to fix this problem, besides a chiller? None of my fish seem to mind the high temps and the coral does not close up, but I do not want to cook everything in the tank either.

[Ninong]

My tank is 120 gallons and I am unable to keep the water temperature below 86 degrees Fahrenheit in the summertime either. We keep the central A/C set at about 74F but my room is always about four degrees warmer than the rest of the house when my metal halides are running. I will have to get a chiller before adding anything else to my tank. I have two 250w 10,000K HQI DE lamps and two 55w PC actinics. I also have two miserable Little Giant pumps (one for system return and one for my skimmer) that add A LOT OF HEAT to the water.

What do you have in the way of pumps or powerheads on your system? They all add heat. How large is your tank? How close are your PCs to the water's surface?

BTW, my tank is also open top but all I have is a single 7" clip-on fan blowing across the top when the halides are on and it doesn't help a whole lot, just a little. And all of my lights are 11" above the water.

[Meric]

My tank is a 125G 72X18X22, with a 25G Sump. I have (3) MaxiJet 1200's providing in tank circulation, plus a Mag 18, submersed, for my sump return. I have an external Protein Skimmer (Prizm Pro), and my Lights are 5" from the water surface. I have (4) 96 Watt Power Compact Lights that do get very hot. I have (2) 4" Fans that blow into the hood, with a 10" Exhaust vent in the rear of the hood.

I believe 86 degrees is pretty close to the limit saltwater fish and corals can take.

[Ninong]

I believe 86 degrees is pretty close to the limit saltwater fish and corals can take.

Natural reef temps often exceed 86 degrees in the warmest months but I am inclined to agree with you that 86 degrees is awfully hot for a reef tank. I think anything above 84 degrees is risky for certain species and probably just as bad is the constant up and down every night when you try to get the water temperature down so that it won't go even higher the next afternoon.

If I decide to break down and get a chiller, I will probably go with 80 degrees for the winter season gradually increasing to a high of 83 degrees for the summertime. Maybe even a high of 82 degrees for the summertime because my circulation is not all that great and if you're going to run a high energy system, you need very good circulation.

I had no problems at all with my tank's inhabitants when my temperature was ranging from 80-85 degrees on a daily basis but then one day when I was away from home for several hours someone did something they shouldn't have done that caused my water temperature to rise to 89 degrees for at least four or five hours. I lost all of the SPS corals in my tank over the next week or two.

[patsfan1130]

Have you tried setting your heater at 70 or so? It is very typical for most heaters' thermostats to be off. you could also try hooking your heater up to a controller which will make it much more accurate and also take the risk out of having the heater fail on you. Humidity plays a big role in tank temperature. I live in New England and generally do not have to deal with high outside temps but this past Tuesday it was only 75 outside but the humidity was 70%. My tanks temp got up to 86 by early evening. I am suprised the 2 fans dont make more of a difference for you though. you could drop your photo period down to 8 hours without experiencing any ill effects depending on what you are keeping. also..if you have an enclosed stand..I find that keeping my stands doors open helps too.

Mark

[Meric]

I ws looking at the layout of my plumbing last night (I got a new sump that I will be putting in on Sunday) and I noticed that my return runs right in between the (2) PC Ballast on the hood. The ballasts are so close to the return that it almost touchs. So I put my hand near the ballast and nearly fried my skin. So I took one of the fans and pointed it directly on the ballasts to keep them cool. Today the temps did not exceed 84 degrees during the whole time the lights were on. Still a little high, but not 86.

I'm guessing that the ballast was heating the PVC return to a very high temp and the water running through it was heating up through thermal transfer. I will be rerunning my return when I install the new sump tomorrow.