Cooling Fans

[Matthew5664]

With the upgrade to MH lighting the fans I have too cool the system are now on a timer to come on ½ hour before and go off 1 hour after, my question is do you think I should have both blowing across between the light and water then up out of the top or one bowing in and one out. Then again you could have them both on the top taking the hot air out drawing cold air in across the water.

In a nut shell; how do I maximise the efficiency of the cooling done by the fans?

 

[Chac]

Hey matthew

I upgraded to Mh's about 4 months ago

My temp is now more stable then when I had a closed tank with T5 PC's

I used to have 2 'Puter fans blows straight down on to the water to cool the tank

Now I dont use any cooling & have no temp issues

Sorry tell a lie, I had to float a block of Frozon RO Water a couple of times last week as the outside temp was around/above the 30c mark & the tank temp did rise slightly

I have also left my main lights off until 7 pm during the recent hot spells

 

[Matthew5664]

Nice one thanks for the info.

My MH are still being 'broken in' and are on for 2hr a day 3-5pm At that time I have two 3" fans to cool but I'm not in at that time too see what temp it gets to and the girlfriend wants on more to do with the tank. when i get home at 5.30 it's at 26.8C as usual drops to 26.2C at night

 

[littleimp]

You can use them effectively by sucking the heat out in the first place but fans don't work by cooling the water (as in blowing on your tea). They work by evaporation, the evaporated water is then topped off automatically using a top-up system with cold water hence cooling the tank. That's why some people have them over the sump.

 

[SkiFletch]

Well Matt, if I were you I'd put some fans in the halide fixture itself to suck air in from the water area, past the light, and then exhaust it out of the hood or fixture. That keeps the actual heat energy from hot air from getting to your tank. I'd then take a second fan and have it blowing at and across the surface of your water to increase evaporation there to dissapate the extra infrared energy the halide puts into your water. hope that makes sense

 

[ostrow]

Some contradictory answers in here. If you search in some of the forums dedicated to reefkeeping, you will find not only practice but also strong arguments and vendor recommendations stating that the fans should be pulling air from outside the tank and blowing in. Direction of air flow inside the tank is a matter of preference and design of your equipment (canopy or no canopy, etc).

But air gets pulled from outside, blowing in. That is also how fixture fans are oriented.