will internal filter contribute to water temp ?

[peterkoh]

while looking around on past threads on fans (ac/dc/diy/factory), something occurs to me. why is it that some folks can achieve as low as 25-26 deg in ambient room temp while some like myself struggle to bring it down to 28 deg. i remember feeling the internal filter when it is running and it feels slightly warm.

does anyone has any evidence that internal filter actually contributes to water temp. ? some of us could be looking at the wrong end of the problem and end up having an array of noisy, unsightly fans that struggle to cool the tank and instead dry up the water faster than expected.

thks.

peter

[Daz]

Not too sure about others. Mine is running on external filter and using 1 x fan to achieve 28 degree.

In view of your question, I think regardless internal or external, the difference could be just 0.5 degree if you are using some fan to lower the water temp. The difference should not be too much

[tawauboy]

internal filter will add some heat into the water. when the motor runs, some of the electrical energy is wasted as heat. and heat has to go somewhere, which is your tank water.

you can verify by switching off your internal filter for a couple of hours.

[Darkkon]

I don't know how the "other folks" can achieve 25-26 degrees like you say. I have 1 fan and on hot days temperature rise as high as 30 degrees even with the fan on. So far the lowest i've hit was 25 degrees, but that was on a terribly rainy day and it's no thanks to the fan. And i am using a external filter, so if your water temperature is also about 28 degrees average, i don't think filter type is the factor.

[benny]

Here an example from my set up of 2 identical tanks in a room with an ambient temperature of 30 degrees.

Tank 1 : 4 X 1.5 X 1.5 Top tier
Lighting : 2 X 30 W FL = 60 watts
Filters : 1 X Eheim Pro II 2028 & 1 X Eheim Pro II 2026 external cannister filters
Others : Air pump + UV light
Temperature : 29 degrees

Tank 2 : 4 X 1.5 X 1.5 Bottom Tier
Lighting : 2 X 55 W PL = 110 watts
Filter : 1 X Fluval 4 Plus, 1 X Eheim Aquaball 2210, 1 X Attman F202. All 3 internal filters rated for 4 ft tanks.
Others : Air pump
Temperature : 28 degrees

Temperature were taken with thermometers of the same make.

From the above, the bottom tank should have a higher temperature as the light is a 110 watt PL and running on 3 internal filters. However, in reality, it is not the case.

Therefore, in my opinion, nothing conclusive can be determined about internal filters increasing significant heat load.

Cheers,

[Alfa Low]

Benny, I think your tank size is bigger that's why the heat generated by filters and lightings is not that significant to such a big water volume plus you have good ventilation in that room right?

In my case (When my 50L tank still with me), my tank temparature was 32C running with Fluval 2 Internal filter, Otto PF800N Int F. After i switched to Canister F, the tank temparature had been reduced to 30C(no fan).

Therefore,
If we put aside other possible factors that lead to fluctuation of water temparature eg, room temparature, heat generated by lighting, enclosed tank without fan etc
Heat generated by internal power filter in
Big tank (3 ft & above)- insignificant
Small tank (2 ft & below) - significant.

[bclee]

Actually it may be roughly worked out.

Using my tank as an example. I have a Rena iV2 (rated at 5W) running in my 50L tank.

Assuming a bad case of 50% effeciency where 50% of power is lost through heat generation. I have 2.5W of heating by the filter.

Heat capacity of water at 28°C = 4.141 kJ/L.°C

2.5W = 2.5 J/s

In 1 hour, I have (3,600s x 2.5J/s) = 9000J or 9kJ of heat generated.

Assuming the tank is perfectly insulated...
9kJ is enough to raise 50L by ...
(9kJ ÷ 4.141 kJ/L.°C ÷ 50L) = 0.04°C

IMO this is quite negligible.

BC

[sherchoo]

BC,
Great explanation. Keep it up.

[peterkoh]

Thks guys for all the feedback.

I'm running a 8 cm fan at 12 volt atm. I had it running a few days ago and just returned home. The water temp is around 27.5 to 28 deg ! Not bad consider I'm only using 1 fan. Will try running it at 6 volt and see if the same temp. can be sustained. Too strong a fan speed is driving down the water level quite quickly.

Based on the feedback so far, I think the energy generated by the internal filter even when it is choked shd be neglible.

[tawauboy]

2.5 watts of heat can heat up 50l of water by 0.04 deg c in 1 hr.
if this heat is kept up for 50 hrs, the water temperature would increase by 2 degrees.
that is assuming that the tank is well insulated.

if the tank is kept at a well ventilated location, there should be minimal temperature rise.
heat from the filter will be dissipated through the tank walls to ambient air and through evaporative cooling.

[bclee]

You ever wonder how much heat your fans is removing in comparison with your internal filter.

Let's do a calculation again using my tank as an example.

I am losing about 0.7l(~0.7kg) of water a day due to evaporation using a fan.

Latent heat of evaporation of water = 2300 kJ/kg

In one day I lose 0.7kg x 2300kJ/kg = 1610kJ through evaporation.

I turn my fan on for 12 hr a day and assuming negligible evaporation at night when fan is off. Therefore the rate of loss of heat by evaporation = 1840 ÷ (12 * 3600) = 0.037 kJ/s = 37W

(The above do not take into the heat loss by force convection. But major portion of cooling will come from the evaporation of water.)

I have having a cooling of 37W just by evaporation. 2.5W of heating from the internal filter is easily removed by your fan.

BC