# Planted Tanks > Beginners' Corner >  Any ways to cool down aquarium water?

## scarnhost

Are there any other ways to cool down aquarium water other than adding ice or using a cooler?

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## eviltrain

some ways are by using:
fan ( you have to top up water quite frequently )
chiller (estimated around $10-$20 increase in electricity bill )
place your tank at the coolest area in the house.
-good luck-

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## zonkkie

some people put in office with 24 hr aircon. 
some put in room with 24 hr aircon. 
mmm.... migrate to cooler countries! :Grin:

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## Wilfred

Move your tank into fridge? put ICE into it as well... :Opps: 
I think all have been spoken by the pro up there...

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## jiajuen900

Some people but bags or bottles of ice in their tanks on real hot days....

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## madnugget

> Some people but bags or bottles of ice in their tanks on real hot days....


my take on this is not advisable, temperature will fluctuate a lot.. i think it will cause more casualty then leaving at it is on real hot days.

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## Shadow

> mmm.... migrate to cooler countries!


Then you will need a heater  :Laughing:

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## Navanod

> some ways are by using:
> fan ( you have to top up water quite frequently )
> chiller (estimated around $10-$20 increase in electricity bill )
> place your tank at the coolest area in the house.
> -good luck-


Permit me to add to your points:

- Stop using a canister filter/powerful pump if you are. The pump dumps heat into the water that raises it above ambient by almost 4 degrees for my tank (running a 2226). Check the wattage of any pumps you're using for the tank and try to have as little wattage as possible.
This method is only valid if your tank is consistently running above ambient temp with a canister/pump. You may have to reduce your bio-load.

- Get a tank with a very large surface area to volume ratio. This may help keep temp as close to room temp as possible but with the same problem as using a fan.

- Reduce the wattage of light you use or switch to a cooler/lower power lights.

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## jiajuen900

depends on the canister filter. Most boyu brands increase your temp more than other canisters. Having little wattage as possible will affect the amount of water being filtered, meaning filter not as sufficient or not sufficient enough for tank. lights in some cases are needed for the plants esp in high tech setup so reducing is not the best solution. But i dont think that lights will affect that much. 

Filter can really raise by 4 degrees?

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## Shadow

I never actually measure, but I doubt canister filter will increase temperature by 4 degree. The water in canister filter does not in contact with the motor. The motor is actually on top. The water contact is only at impeller magnet area. 

You can try simple experiment by measuring the temperature right before the filter inlet and right after the filter outlet. Right before and after the filter and not at the tank side, this is to limit external variable that might effect the measurement. Also use the same thermometer.

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## tawauboy

4 degrees rise in water temperature? it may be possible if there is no air circulation on the surface of the tank.

try covering the tank for a day and check the temperature. next, uncover the tank for a day and check the temperature again.

the impeller cavity can become hot. water circulation during pump operation cools it. when my filter broke down, i found steam rising from the impeller magnet when i took it out from its cavity.

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## Navanod

> I never actually measure, but I doubt canister filter will increase temperature by 4 degree. The water in canister filter does not in contact with the motor. The motor is actually on top. The water contact is only at impeller magnet area. 
> 
> You can try simple experiment by measuring the temperature right before the filter inlet and right after the filter outlet. Right before and after the filter and not at the tank side, this is to limit external variable that might effect the measurement. Also use the same thermometer.


Hi Shadow
I think tawauboy has said what I wanted to say.
I use liquid to cool my computer as well so I did quite abit of homework on pumps and heat dumps.
Most water pumps I know use the water running through it to cool the rotor as they usually have plastic housings with poor heat conduction to outside air.
Since the loop can only lose limited heat from the water+tank surfaces and the pump rotor housing, any excess heat not lost will heat up the water and the pump rotor (increase temperature).

The experiment you suggest may not work because the water in the entire loop will reach an equilibrium temperature where the total heat loss is = heat produced by the pump and all the water will be at almost the same temperature, even for the inlet and outlet of the canister/pump.

The details of how this happens is very long and involves thermodynamics which looks at the specific heat of water and the effects that temperature differences between pump, water and air have on the heat transfer rates from pump to water to air.

To put it simply, when the water hits a certain temperature, the heat transfer rate from water to air (heat loss) would be equal to the heat transfer rate from pump to water (heat gain).
For my case, the water had to be 4 degrees higher than ambient air in order to lose heat fast enough to match the amount of heat generated by the canister.

_(The long winded form, please don't read unless you're really free)_
The is because the greater the temperature difference, the faster heat moves from one medium to another. So as the water heats up, it is able to lose more heat to the air much faster while the amount of heat moving from the pump to the water will slow down. This heats up the pump (pump temperature goes up) and causes heat to flow faster into the water again, heating up the water somemore.
This cycle continues until the water and pump temperature reaches a point where the water is so hot, it is able to lose the exact amount of heat energy being dumped into it by the pump to the air. This where the water and pump will stop increasing in temperature.

This is why the water doesn't eventually boil although initially, the heat loss is less than heat produced.

Also, due to the relationship between heat transfer rates vs temperature differences between water and pump, water at the inlet and outlet of the pump would not show a significant difference in temperature and is said to be at a thermo-equilibrium.

Let me catch my breath now :Opps:

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## Blue Whale

Scarnhost,

I am curious, why did you ask this question in the first place? Is your tank really that warm or you are preparing yourself due to the recent hot weather?

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## Shadow

> when my filter broke down, i found steam rising from the impeller magnet when i took it out from its cavity.


wow can't imagine it become that hot until steaming  :Shocked: .




> The experiment you suggest may not work because the water in the entire loop will reach an equilibrium temperature where the total heat loss is = heat produced by the pump and all the water will be at almost the same temperature, even for the inlet and outlet of the canister/pump.


It should work the reason I suggest to measure right at the filter in and out (not at the tank) is because I'm trying to cut off the external variable. By measure at in and out, you can ignore the heat loss to the air as well as heat gain from the light. The heat measured will be purely from the filter.

since you measure tank temperature 4 degree higher than ambient temperature, that mean the temperature measure at the output of the filter should be more than 4 degree above the ambient temperature. 

heat generate by filter - heat lost to the air = 4 degree

actually I think it should be the rate of heat generated and the rate of hear lost.

different filter may have different heat performance though.

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## Navanod

> since you measure tank temperature 4 degree higher than ambient temperature, that mean the temperature measure at the output of the filter should be more than 4 degree above the ambient temperature. 
> 
> heat generate by filter - heat lost to the air = 4 degree
> 
> actually I think it should be the rate of heat generated and the rate of hear lost.
> 
> different filter may have different heat performance though.


I understand what you're trying to say but what I'm trying to express is too complicated to discuss here and would be totally OT.

IMHO, An experiment to see how much a pump/canister would heat up a tank would be:

Running the tank with a pump/canister for 12 hours (for equilibrium temp to be reached), noting down the tank water and ambient temp and minus the ambient temp from the water temp to obtain the delta temperature (ie. how much above ambient).
Remove the pump/canister and repeat the above measurements after 12 hours to obtain a 2nd delta.

The 1st delta minus 2nd delta would give the temperature that the pump/canister would heat a tank up by, and this method would negate any external variables such as lightings, heat loss from water surface/evaporation and most importantly, any difference in ambient temperature during the time of readings.
Note that any changes in wind/airflow over the tank will affect the accuracy of the result. Best to shield the tank from wind while testing.

Incidentally, my tank which suffered from the 4 degrees increase had very little wind and a rather reduced surface area to volume ratio, which may explain the large increase.

As you've pointed out, different filter may have different heat performance and the tank surface area, ambient, average rate of airflow over the tank's surface (causing additional heat loss from latent heat of evaporation) will all affect heat loss and eventual tank temp.
Its best to test this out on a case by case basis if one wishes to see if changing/removing a pump/canister will help lower tank temperatures.

With all that being said, I for one gave up and went for a chiller. Simply too much trouble using other methods to cool the tank.
Cooling the PC on the other hand, is very fun with water  :Grin:

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## elmo

Thats very interesting...cooling pc with water...first time see this..maybe i 'mountian tortoise'.. :Grin: 

Care to share more? :Smile:

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## Blue Whale

Navanod,

This would interest you. http://www.heatsink-guide.com/

But rather than allowing myself to be crazy on heat sink, I took another path. Notebook. Energy efficient and less heat.

Shadow,

I do agree filter will increase the temp a bit. About 1-4C on average. Usually heat will be lost to the air, so still more efficient to keep your house cool via ventilation aka "Open the right windows to allow the house to cool down". It is not practical to open all the windows when you are not home. Controlling ventilation will also contribute to cooling the tank down.

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