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Cooling a fish tank with computer fans

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JoshOohAh

Member
Joined
Dec 9, 2009
Location
Canada
Yea I know this sounds a bit off topic but this is the section it fits best under. Anyways I am getting my new fish sometime this week and I set up my tank and it's slightly warmer than I wanted it to be. I needed to make it like 3-4 degrees cooler. So I rummaged through old computers and I collected all the old case fans I could get.

So basically I have 1 80mm blowing air in and 2 ball bearing 10mm pulling air out. I was actually surprised that the 2 small ones have a lot of power. Anyways I hooked them up to a 3 pin to Molex connector and connected them to an old PSU. I short circuited the green and a black wire on the 20 pin connector and they are running fine. Now I attached them to the the lid of my tank so they are directly over the water. I lowered my water level so there is a good inch of space between the water and the fans.

Now my concern is that when water evaporates it will get on the wires of the fan and cause something to screw up. I ensured the wires are fed out of the tank and they are connected no where near the tank. Should I be concerned? What is the worse that could happen if some water did manage to get on the wires? Should I do something to prevent this or should I just give up on the whole idea?
 
You should be fine. People used to run fans in a bong (tower) cooler and that had a lot more humidity than this.
 
I can almost guarantee you won't have water issues. It's doubtful it'll cool enough to condense, and even if it does condense, it's likely it won't short anything.

What my question is, will blowing air over the water really cool it? There really isn't much surface area for the heat from the water to be transferred.
 
You should be fine. People used to run fans in a bong (tower) cooler and that had a lot more humidity than this.

I can almost guarantee you won't have water issues. It's doubtful it'll cool enough to condense, and even if it does condense, it's likely it won't short anything.

What my question is, will blowing air over the water really cool it? There really isn't much surface area for the heat from the water to be transferred.

Thanks both for the reply!

But to answer your question yes it does cool it to exactly what I wanted. I had it at 23 Celsius and after putting on the fans for a couple hours I'm down to 20.5 Celsius. Also I just realized one of the fans isn't working so I will be just replacing one of the other 10mm fans. With 1 less fan it is still working just the way I need it to.
 
Another option would be to place a solid or hollow 1" pipe into the tank and let he fans blow on that.. heat will pull out of the water and the fans would cool the pipe down.. course the fish may not like it!
 
I have a friend that is into saltwater reef aquariums. He has a 3x120mm fan setup blowing across the water on his tank. It works very well and they actually sell a similar fan setup on a lot of reef aquarium sites.
 
It should work great, that's the single most common method of dropping aquarium temps.
The fans should be fine, their hubs typically run in the 75-85*f range, warm enough that the moist air won't condense on the electronics.

It will, of course, speed evaporative water loss.
 
If he has a burly lighting system he may not even have a heater, high end aquarium lights are between 2w and 10w per gallon of size (>5w is mostly saltwater only). If the room temp is in the 70s it's not hard for the light alone to push the tank higher then you want.

Worse, if the room temp is in the 80s you need a chiller, or very specific fish. Most tropical fish are far from happy in 80*f+ temps.
 
Another option would be to place a solid or hollow 1" pipe into the tank and let he fans blow on that.. heat will pull out of the water and the fans would cool the pipe down.. course the fish may not like it!

Beast idea! Too bad it's not practical. Also I'm not sure if this would work so well because the tank is at room temperature but either way a still sweet idea.

I have a friend that is into saltwater reef aquariums. He has a 3x120mm fan setup blowing across the water on his tank. It works very well and they actually sell a similar fan setup on a lot of reef aquarium sites.

I think that if something goes wrong with my fans I will do something like that. I just wanted a cheap way fixing the problem

It should work great, that's the single most common method of dropping aquarium temps.
The fans should be fine, their hubs typically run in the 75-85*f range, warm enough that the moist air won't condense on the electronics.

It will, of course, speed evaporative water loss.

Yea I'm already noticing the water levels decreasing, but it's no problem to change the water every week.
 
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