# Temperature Fluctuation



## harriw (Mar 7, 2008)

Hey folks,

Does anyone else have problems maintaining a consistent tank temp when the weather starts to warm up? I'm having trouble with both tanks now - a 72G BF with a 250W topfin heater, and a 10G quarantine/hospital with a 50W cheap-o that came with the tank. Ever since the outside temp warmed up a week or two ago (average around 70 now), my tank temps have been going through the roof (I've found the tank at 84 deg. when I get home from work more than once). Funny thing is, with the windows open, the temp in my livingroom is really only 2 or 3 degrees warmer than it was all winter (though it was better regulated by the furnace). I've been having to unplug the heaters at times during the day to keep from boiling the fish!

Do these cheap-o (I'm including the topfin in that category) heaters have a minimum duty cycle? I have walked by the tank and seen the heater on when the tank is clearly WAY above the target temp (the top fin doesn't have temp indicators on its dial, but I've had it for a while, and have a pretty good idea of where to set it to get what temperature). Should I ditch the topfin and get a higher quality heater, or will I have the same problem with one of them?

I don't believe water movement/heater location is a problem, but just to share, I mount the heater vertically on the back wall. An emp 400 creates top water movement, and an UGJ system moves water from underneath. I did have the heater near an intake for quite a while, but it's more or less centered between two intakes now, about a foot or two away from each. My 72G is also located right next to a Bay window, but I keep the shades drawn 24/7 (we like the tank there, and would rather "eliminate" the window than move the tank). Some light still does get through the blinds of course, but I think it's pretty minimal. I'm open to getting some heavier curtains as well to completely block the sunlight if you think that's a problem. Temp has been regulating well in this location for a few months though, up until the outside temp warmed up (we've had plenty of sunny but cold days during that time).

Any thoughts? Any input would be greatly appreciated! Thanks!

-Bill


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## MalawiLover (Sep 12, 2006)

Where is the thermometer in relation to the heater?


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## hollyfish2000 (Aug 23, 2007)

Yes, I'm having the same problem. Maryland right now is 50 at night and 80 during the day and I can't figure out whether I want the heat on or the A/C on and the tanks are fluctuating by 4 degrees or so, except for my 10 gallon guarantine tank, which was swinging wildly. Up to 84 at one point. I turned the AC on and turned the heater off and it plunged to 74. I finally gave up and put the fish in the main tank because I figured the temp swings weren't good for him and the main tank was more stable, temp wise.

Then my cleaning people somehow knocked my house thermostat and I came home on Friday night to the AC roaring and the temp at 64. I don't even have it that low in the winter! All the tanks were running cold at that point . . . Sigh.


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## harriw (Mar 7, 2008)

Glad to hear I'm not the only one going through this! Anyone have any solutions they've found? I'm thinking of putting the heater on a timer for spring/fall so that it's turned off during the day when it's hot, then turns on at night when things cool down.

How do you folks deal with summer though? If it's 85 degrees out, the tank is going to get at least that warm (do glass tanks have any green-house effect?)

I really do think the problem I'm seeing now though is due to a minimum duty cycle on the heater. During the winter, I keep the house at 68-70, which stays pretty much fixed. The tank stays pretty well regulated as well, but I can't get it to go below 80 to 81 degrees. Now, my livingroom is at about 76 during the day, and I've seen temps of 85 or 86 in the tank with the heater plugged in. The same minimum on-time for the heater would produce a similar temperature increase over the room temp, resulting in what I have now.

So, what heaters does everyone use, and do they have minimum on-times, or are they perfectly happy being plugged in all summer and never turning on at all?

Oh! I have a glass thermometer in the tank suction-cupped to the front face. It's near the top of the tank, on the right hand side (away from the window). So it's relatively far from the heater to avoid a "hot spot" around the heater. I'm contemplating getting one of those fancy thermometers with better accuracy, digital readout, alarms, etc. to make sure I don't cook the fish.

-Bill


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## Bmay1011 (May 23, 2007)

I too have similar temperature control issues. I use sump filtration, so the first thing I did was add louvers to my tank stand to help ventilate the heat. I've also added fans, connected to a thermostat, which mount over my sump and make a significant impact on keeping the temperature under control. Evaporation is critical to water cooling. I also make daily small water changes when I get home from work and use cold water to refill. I make every attempt to keep my temperature controlled between 77 and 80 degrees. Keeping your tank out of direct sunlight and leaving a couple of windows open to circulate outside air couldn't hurt either.

-Brad


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## Deeda (Oct 12, 2012)

During the summer, I replace the smaller section of my hinged glass lid with a piece of eggcrate cut to size. Keeps the fish in, the cats out and allows the heat to dissipate.


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## harriw (Mar 7, 2008)

Oooooh!!! :idea: That's a good one! I did just install an UGJ system recently, and am running 1/2 of it from my HOT Mag's output. The HOT Mag used to just spray all over the surface, and anyone who owns one of these can attest to how much surface agitation they cause. Although I still have the emp 400 and a small air bubbler (more for looks than anything else), but my surface agitation defintiely took a hit due to the UGJ's. Probably not helping my situation, huh. I do try to minimize the sunlight despite the window, and keep windows open in that room to try to get a breeze in there.

The wife will never let me put a sump in the (carpeted) livingroom, but that's a great idea too. I scaled back my "lights on" time a bit too, but I only have a single 48" tube on the 72G tank, so I don't think it's contributing much.

-Bill


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## harriw (Mar 7, 2008)

Thanks everyone for the input! Here's what I've done:

I picked up a pair of new penguin 1140's this evening to run my UGJ's off of rather than the filter output (and a 170GHP power head I had laying around). So now my HOT Mag is power-washing the surface of the tank again.

Also got a new marineland visi-therm stealth heater (LFS allowed me to return my old heater, so it was basically free). I noticed some cracks in my old heater, and the top was loose as well - I think my heater was going bad in addition to my weather problems.

So, we'll see if a new (better) heater, more surface agitation, and more water flow (new pumps) will help my temp issues.

-Bill


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## pcrawford1044 (Apr 19, 2008)

there are too many problems with top fin heaters get a stealth or a jager i just got rid of my hydor theo heater as it was sticking also and got a stealt h250 for my 75 gallon


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## harriw (Mar 7, 2008)

Well, it's been a bit cooler the last few days, but temperature has been MUCH steadier. I LOVE the stealth (also the 250W model) - you can barely even see it on my black background. Figured out the quarantine tank too - it came with a 25W hydor theo that was cooking the tank. It turns out the temp dial is about 10 degrees off - set it for 71 or so, and you get about 81. Thanks for the tips everyone!

-Bill


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## fishyfishyfishy (Dec 24, 2005)

One of the problems as well in the summer/warmer months is that there is more humidity. Without the air being as dry, there's less evaporation in the tanks. (Ever realize you add much more top off water in the winter?) Evaporation is a cooling process and therefore helps keep the water temperature down. That's another reason removing the tops helps with the temp...it's more than just letting the heat escape...you're increasing evaporation by exposing more water to the air.

Like one of the other posters, in the warmer months, I use clip on fan attached to my sump that is controlled by a temperature controller. The blowing of the air across the water in the sump increases evaporation and therefore cooling. It lowers the tank around 3-4 degrees which is enough to keep me in the safety zone.

Get a sump!!! There's more risk to your carpet with a canister than a sump!!!


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## stslimited84 (Oct 5, 2007)

A great thread.


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