Tank Too Hot, How Can I Cool It Down?

[FishayFishay]

So my 36 Gallon Bowfront has been at 79 degrees and I decided that that's fine, but today it's 80.5 so I need to turn it down a little, like 78 degrees. I set my Aqueon Heater to 76 but, well, it's not 76. My dad said to unplug the heater for a little bit, thoughts?

 

[Lilibeth_Seasong]

How long has it been since you turned the heater down? Depending on the temperature of the room it may or may not get that low. Your fish should be fine with the slightly higher temperature for awhile.

What kind of thermometer are you using?

 

[FishayFishay]

How long has it been since you turned the heater down? Depending on the temperature of the room it may or may not get that low. Your fish should be fine with the slightly higher temperature for awhile.

What kind of thermometer are you using?

I am using a ZooMed internal thermometer. The heater has been on 76 since a week ago and I turned the heater off an hour ago. The temp. now in the tank is 79.7, which is better but I'd like to get it a little lower. The temp. in my room is 72.

 

[FishTank Maniacz]

You can always float some ice in ziploc bags

 

[jileha]

You can try and set the temperature even lower to see whether it has any effect on the actual water temperature. If not, your heater is not working the way it should - which it doesn't seem to do anyways. With a heater overheating, there's always the risk it could cook your fish any time.

Constantly unplugging your heater and plugging it in again will cause too many, too strong temperature fluctuations to be healthy for most fish. You also need to remember all the time to plug it in again before the water cools off too much. Unlplugging a heater "works" only if the room temperature is so high to cause the water temperature go higher than what it should be,

If the heater doesn't work the way it's supposed to, toss it and get one that does.

 

[ricmcc]

Almost all heaters that I have used seem to offer something different than what is indicated on the temp. that use have actually set it to be at.
For that reason, I usually give my heaters a test run, as it were, and take the water temp. with an infrared thermometer (which is very accurate, but is designed for keeping herps, so stir your water a little to allow for both exposure to the ambient temp., and of the cooling effect of evaporation).
If you can find a constant, as in, 'this heater is always heating to plus/minus whatever degrees of its setting, than you have no problem; just set the heater to allow for a known constant error.--------rick

 

[FishayFishay]

Alright thanks all. Wait so are heaters supposed to help cool the water too or just heat? I figure it's just heat...About the floating bags of ice, I think I'll try that. Since ice is really just frozen tap water, will any condensation coming from the bag affect anything in my tank? By the way, the temp. is now at 79.3 degrees.

 

[ryanr]

Hi,
First, let me say that 80.5 is not cause for concern, a little warm, yes, but not bad.
I've just come out of a 4 day heat wave (four consecutive days above 105!) - my Freshwater tank was sitting at 86 for 4 days, with no stock loss.

Heaters will only heat the water. Those that have a temp setting also have a thermostat, and will only activate when the tank cools.
For as long as the tank is above the set temperature, the heater will not kick-in. Thus, there's no need to unplug it.

There are a number of things that can heat the water:
- Ambient Temperature
- Lights
- Equipment such as filters use the water to cool themselves, transferring their heat to the water.

Things you can do:
- If you have a canister filter, insulate the tubes to prevent ambient temp influencing the water
- Reduce the intensity and/or duration of lighting
- Open the hood/Remove glass lid to allow heat to escape
- Float ice in the tank (ziplock bag is good, so is a soda bottle)
- Blow a fan across the surface, will increase evaporation, which helps cool
- DIY Chiller (search Fishlore, there's a video on here somewhere for a great DIY chiller)
- Add a chiller (expensive, but permanent option)

Also, run an airstone to help oxygenation in the water - warmer water holds less oxygen.

 

[Viriam Karo]

Alright thanks all. Wait so are heaters supposed to help cool the water too or just heat? I figure it's just heat...About the floating bags of ice, I think I'll try that. Since ice is really just frozen tap water, will any condensation coming from the bag affect anything in my tank? By the way, the temp. is now at 79.3 degrees.

Remember that condensation is outside water settling on colder surfaces. The water from inside the bag doesn't leap past the plastic to the outside So condensation would be ambient moisture from the room/tank water anyway.

 

[FishayFishay]

Hi,
First, let me say that 80.5 is not cause for concern, a little warm, yes, but not bad.
I've just come out of a 4 day heat wave (four consecutive days above 105!) - my Freshwater tank was sitting at 86 for 4 days, with no stock loss.

Heaters will only heat the water. Those that have a temp setting also have a thermostat, and will only activate when the tank cools.
For as long as the tank is above the set temperature, the heater will not kick-in. Thus, there's no need to unplug it.

There are a number of things that can heat the water:
- Ambient Temperature
- Lights
- Equipment such as filters use the water to cool themselves, transferring their heat to the water.

Things you can do:
- If you have a canister filter, insulate the tubes to prevent ambient temp influencing the water
- Reduce the intensity and/or duration of lighting
- Open the hood/Remove glass lid to allow heat to escape
- Float ice in the tank (ziplock bag is good, so is a soda bottle)
- Blow a fan across the surface, will increase evaporation, which helps cool
- DIY Chiller (search Fishlore, there's a video on here somewhere for a great DIY chiller)
- Add a chiller (expensive, but permanent option)

Also, run an airstone to help oxygenation in the water - warmer water holds less oxygen.

Remember that condensation is outside water settling on colder surfaces. The water from inside the bag doesn't leap past the plastic to the outside So condensation would be ambient moisture from the room/tank water anyway.

....Well I seem to have forgotten everything from 6th grade, forget what I said about condensation! And haha 100 degrees seems a long way away here, we're expecting snow on Wednesday! If your fish can survive at 86, I think 79.2 is fine for me right now!

 

[Mamajin]

are heaters supposed to help cool the water too or just heat?

Both actually. Once you set the heat to a specific temperature, the heater is supposed to then keep the temperature stable. A fluctuation of a few degrees here and there is fine. You just don't want big fluctuations as this can cause stress, which in turn lowers the immune system making them susceptible to diseases.

 

[ryanr]

I like to think that a heater maintains a minimum temperature in the tank, and a chiller maintains a maximum temp.

I explain the concept here:

As mentioned, tanks will naturally fluctuate throughout the day, lights being the major contributor to heat. For most tropical species, keeping the temp between 75 and 81 tends to be just fine.

For those that keep the ambient temperature at or around 71-73, typically a heater is all that is needed. The heater will keep the tank at the set temp.

Once the temp goes above the preset, the heater will simply not activate. It won't do anything to actively cool the tank back down to the preset, but by not activating, it may allow the tank to cool naturally if the conditions allow it (ambient combined with equipment).

 

[MrFishFood]

Put your thermometer in a glass of ice water to see what it reads after 10 minutes. Mix the ice and water every so often to keep the water ice cold. The thermometer should read 32°F. If not, use the amount over or under as a correction.

Example: I have a Coralife digital thermometer and an old glass thermometer. The glass thermometer reads about 32°F to 33°F in ice water, the Coralife digital thermometer reads 33.5°F.

I have to subtract 1.5°F from my Coralife digital thermometer. When I do the correction on the Coralife, both thermometers read the same. The Coralife is precise in that it reads the same each time, but the accuracy is off buy +1.5°F.

Lighting will also increase the water temperature. My 29H freshwater aquarium rises 1.3°F degrees when my 24" dual T5HO Odyssea light is on.