[cS]

I will soon embark on this DIY cooling fans project. The directions are easy enough to follow and the whole setup seems very simple to construct. I wonder if there are any precautions or recommendations that the veterans would like to advise?

I have one particular question. The fans will be mounted on top of the canopy such that it will PULL hot air from inside the canopy to the outside. Is this an efficient system? I've read references in which hobbyists position the fans so that air is blown across the water surface.

Thank you for your input.

 

[gpodio]

The way they have done it here it would make more sense to blow air onto the surface itself. The idea is to cool the water via evaporation. If on the other hand you need to get rid of hot air from inside the canopy, you'd be better positioning the fans so that they blow directly out of the canopy, not towards the top inside of the canopy itself. I guess you could have one fan blowing down and one up

Giancarlo Podio

 

[MiamiAG]

Hi,

This is an excellent idea for cheap evaporative cooling. However, I wouldn't point them down as shown in your link. Cut holes in your canopy where the fans would be located. They should blow in across the water surface. If you have them blowing out, they will rust from the high moisture levels.

Good luck.

 

[apistaeasy]

sounds like a lot of extra work to me. i simply bought a little personal fan with a clip on it, and on days when i know it will get really hot i clip it on to the side of the tank, blowing across the water. the setup is amazing, and will drop the tank temp at least 2c (depending on how much wind hits the water)

 

[Sir_BlackhOle]

I like the idea and agree with art, you should have them blowing across the waters surface to minimize corrosion from humidity.

 

[Daemonfly]

I think placement would depend on what you really need to do. If you need the evaporative cooling, then aim the fans at the water surface. If you just need to vent the heat from the lights, then I'd have the fans up high in the canopy, blowing out. If it's still too warm for either solution, then a mix of both should work.

 

[BudiPT]

I think fan is meant for evaporative cooling, as it does better cooling job by blowing the water surface than sucking up canopy heat. Distance and therefore force of the blows seems more important.
I have 2 tanks (96G & 17G) with 1 fan each where I position it at the corner of the tank about 3" from the water surface. Both are exactly the same type of fan. By putting it at the corner facing straight down, it never blow accross the whole surface, only portion of it. Amazingly, both giving me 25-26 C on ambient temperature of 28-30.

 

[cS]

Apologies for the delay in response. I've been marinating over the issue and here's a visual of my situation.

As you can see from the picture, the hood is completely sealed and the only ventilation is the open backside for equipments/etc. I had it completely sealed because I don't want any light to spill into the room. Given the hood's design and my personal preferences of light spill, if I were to place the fans so that it would blow across the water surface, then the fans must be installed in the front side of the hood so that air is driven out the backside of the hood. This is a viable option but that would cut down on the space available for me to do maintenance on the tank.

The second option would be to drill some openings on top of the hood and place fans there so that air is sucked from inside the hood to outside the hood. No light will be spilled out into the room through the fan openings because those AHSupply reflectors concentrate much of the light output downward. However, as stated above, sucking hot air is not efficient.

I hope that I have elaborated clearly enough to give you a better understanding of the dilemma. Please advise me of any alternatives. [-o<

 

[gpodio]

You can also install two fans in the rear, one blowing in from one side and ither blowing out from the other, this would create a circular current going in from say the left side of the back opening and exiting from the right. Even a single fan blowing in from one corner will create a circular pattern, just make sure it's blowing towards the front of the canopy, the air can't keep going in without it coming back out so it should work just fine. Another solution is to use the flot blowers that are sold to insert in front of unused PCI slots, these can be fixed to the top inside of the canopy and they blow out to the side, just point the flow towards the back opening. I'll be using a mixture of both of these for my reef tank.

Hope that helps
Giancarlo Podio