Fan in Hood

[MarkW19]

I'm thinking of adding a computer fan to my tank lid...but I don't want it to cause more evaporation in the water so that I have to do more top-offs.

Basically, if I take the lid off my tank then my tank temp. goes down about 0.5°C (when the lights are on). So I'd like to keep the lid on but blow all the hot air out...

There's a hole I've made in the right of the lid (where all the filter pipes fit through etc.) so do you think I could mount the fan at the left of the lid and have it blowing the air across to the right? This shouldn't cause any extra evaporation should it? And do you think it'd be efficient in cooling my lid down?

Are computer fans very quiet? Or even silent?

And, would it be possible to put a thermostat onto it with little effort (and make the fan and thermostat suitable to be in an aquarium lid, ie. encase them or whatever) so that the fan turns on or off with the heat??

 

[seaham358]

I bought 2 fan on ebay dont remember where. I don't even know they are running and they have a sensor on them for temp control. I think they run 24/7 never checked because as i have said they are quiet.

 

[MarkW19]

So they're in your hood? Is there a hole in your hood for the hot air to get out of? Does it cause more evaporation?

 

[Atari]

Evaporation is what cools the tank down so you can't really have it both ways.. the fan will definitely increase evaporation.

 

[MarkW19]

Well, as soon as I open my lid all the hot air comes out (you can feel it) and then the tank temp. slowly goes down about 0.5°C over a couple of hours. This is just with the lights on of course.

I don't do any top-offs because I don't need to (tank level doesn't go down much and SG doesn't increase/decrease over the 2 weeks until I do a waterchange).

If I put a fan in there and keep the lid down, won't it just do the same job as opening the lid and just get the hot air out of the top of the lid? ie. not cause extra evaporation like opening the lid doesn't? The fan won't be blowing onto the water because there's an acrylic sheet above the water that the lights etc. sit on, then the wooden lid is placed above them.

 

[Gatorfreak]

When shopping for fans look for something with a sound rating of 22 dB or less. You won't be able to hear it unless you put your ear to it.

 

[seaham358]

I have them hanging on the back of the canopy blowing in to bring in cool air and there is a gap on the top of my canopy where the hot air gets pushed out. I cut no hole in my canopy... I know guys who run one blowing in and one out

 

[MarkW19]

If I put the fan at the left and blow it across the lights to the right (where the hole is) do you think it'd get rid of the hot air? And presumably not cause any extra evaporation because it's nowhere near the water?

 

[Shultz]

I mean no offence here.

Curio says that you are going to a lot of trouble setting up your tank, yet you are trying all ways of getting out of toping up maybe a ltr or so a day?

Is it cos you don't have an RO unit or storage for water? I change 10% per week & topup 1-2 ltrs per day & I don't use maybe 6 gal per week all in?

Cheers Shelton.

 

[seaham358]

It should help can't telll you about the evap because all tanks are different.
Why so worried about some extra evaporation?? My tanks get topped of every day so your lucky if you can go 2 weeks betewwn them. Top off's are just part of the hobby.

 

[MarkW19]

Shelton: I dont top-up at all at the moment. I dont need to. My SG doesn't change over the 2 weeks between water changes, and my water level doesn't change either. So, I seem to be lucky in that I don't have to do this part of the hobby.

I want to be able to get around the heat problem without causing evaporation, because I don't want to have to top-off when I've never needed to before. If I can open the tank lid and solve the heat issue without effecting evaporation, then I'm looking for a way to tackle the heat problem in the same way (ie. in the lid, not the water) but with the lid down. ie. not causing unnecessary evaporation. If I can avoid extra work, then I will do! As we all would, if we have the choice!

I do a lot of work with my tank, as we all do, so anything that can be avoided is a bonus

 

[seaham358]

I hear you extra work is something I can do with out also. try 1 fan and see what happens can't hurt......

 

[MarkW19]

Yeah, gonna get someone I know who's good with electronics to do a small system with a thermostat in it...

Only problem is the fan can't be any taller than 7.5cm. Could be tricky...

 

[seaham358]

??????? 7.5 cm?????in inches what is that 8O ...... US here and when I went to school we did not do much with the metric system.

 

[MarkW19]

Hehe...not too big, 3".

 

[Shultz]

Shelton: I dont top-up at all at the moment. I dont need to. My SG doesn't change over the 2 weeks between water changes, and my water level doesn't change either. So, I seem to be lucky in that I don't have to do this part of the hobby.

I want to be able to get around the heat problem without causing evaporation, because I don't want to have to top-off when I've never needed to before. If I can open the tank lid and solve the heat issue without effecting evaporation, then I'm looking for a way to tackle the heat problem in the same way (ie. in the lid, not the water) but with the lid down. ie. not causing unnecessary evaporation. If I can avoid extra work, then I will do! As we all would, if we have the choice!

I do a lot of work with my tank, as we all do, so anything that can be avoided is a bonus

Heheheheheh, well all I can say is you are the first person I've known in this hobby so far that doesn't topup??? I know what you mean about work, but it takes me less than 5 mins to go down to the shed, get a ltr of RO water in my jug & come & pour it in the tank as I'm normally buggering about doing other things?

Anyways if 3" is what you can use that would be a standard 80mm fan. these tend to be whiny & when you lower the voltage of course you lower the amount of air movement... you might just be better off with some more holes in the lid? If you can get hold of a secondhand one better to try before you buy

Cheers Shelton.

 

[sevise]

You could try cutting some vents in the canopy. Some vents near the bottom and then at the top would allow the air to naturally circulate. It may be just enough cooling to drop the .5C you want.

 

[MarkW19]

If I cut holes in my lid, then the lights will shine through them, casting strange patterns on the wall...

 

[seaham358]

go to ebay and type in aquarium cooling fan and you will get a few hits. I was looking for what I bought, its not there any more.....

 

[austinsdad]

Maybe try the eggcrates for lids. Check the hardware store in the lighting section. I think they're 2' x 4', white plastic grids for ceiling light fixtures.