Fan Placement on 55gal

MtuPup · #1 (**permalink**) 09-24-2009, 01:52 PM

Ok I'm diving into a whole new realm - controling air flow in a frog tank. As with all my tales, I have some real world experience. One of the controls systems my company does is for HVAC units. So when I start having mold issues and condensation on the glass, my first thought is I need air circulation and I need it fast.

So far my solution is the typical computer fans - what i'm not sure is the quantity and the location the fans should be in. All I can think is that I need to create some kind of positive pressure in the tank and the air will do it's thing.

Any help is, as always, greatly appreciated.

Epiphile · #2 (**permalink**) 09-24-2009, 02:33 PM

Good on you for moving the air around in there- the inhabitants will thank you, I'm sure. I've been playing with these lately too, and have found a few ways will work- I have an 80mm fan blowing from the top center of the back of the 20 gallon tank towards the front glass and it keeps it pretty clear, for the most part. I also have one in a 30 gallon mounted to the top that blows air down along the front glass, and that works quite well too.

As far as quantity, I would imagine you shouldn't need many- a lot of people even run a single one at half power.

MtuPup · #3 (**permalink**) 09-24-2009, 02:43 PM

Right now, I'm inclined to mount one at each front corner pointed down into the tank ( a possible third and fourth in the middle on either side of the support bar). I found a few 5 switch molex boards so I was thinking it might be cool to have the easy availability to turn on each fan and maybe even hook up some red LEDs into the tank for night viewing.

Epiphile · #4 (**permalink**) 09-24-2009, 02:51 PM

One of the problems I've had was trying to get the fans mounted just right- they need to be a certain distance from the top so that they can take in enough air to run properly. Also, they tend to vibrate and can make a bit of a racket- I've yet to find a really good way of isolating them so that they're quieter.

I was thinking of moonlights, too, but I wouldn't have to worry as much about waking any occupants up- I want to rig a couple 4100k (moonlight temperature, apparently) LEDs to come on when the big lights go off. Not enough to register with the plants, but enough to see by. Wiring those things looks a bit intimidating, but I guess it's just simple math, really.

MtuPup · #5 (**permalink**) 09-24-2009, 03:19 PM

I've got two versa tops, i plan on just cutting the corner out so the fans are sucking air from outside the tank. When I make a full enclosed lighting hood I'll have to do some venting,

As far as mounting, I'll probably just tack them in with a few screws - maybe to eleviate from any vibration issues, put a line of silcone on the edges that are attached to give the fan some play but absorbing a majority of the vibrations.

Epiphile · #6 (**permalink**) 09-24-2009, 03:51 PM

Leave yourself a bit of room to experiment with how much air you're drawing in- I've learned the hard way that a fan has the potential to make your tank as dry as the room it's in.

MtuPup · #7 (**permalink**) 09-24-2009, 04:00 PM

I'd like to have some sort of variable resistor in line with each fan (dimmer switch) so I should be good - considering I'm flirting right around the it's raining humidity level inside the tank (90%+) with the ultrasonic humidifier and water pond.

Epiphile · #8 (**permalink**) 09-24-2009, 04:25 PM

ADDA also makes a waterproof fan. How waterproof they'll actually turn out to be in the long run is anyone's guess, but that's been a recurring problem for me- fans burning out from the moisture.

MtuPup · #9 (**permalink**) 09-24-2009, 04:34 PM

good tip....I'll see if i can track some of those down - if not for now I'll use the cheapies and just replace them with the ADDA's when they burn up.

froggsong · #10 (**permalink**) 09-24-2009, 07:41 PM

I'd think that the best placement of the fans would be in the back corner, angled so that they are blowing across and down the front glass, meeting in the middle.

As for the vibration, I'd think that you could sortof add them into the BG while you were building the tank, leaving a space behind the fan with ways for air to get behind them, and having the foam just around the sides. The foam would absorb the vibration, reducing the sound. I'm having trouble thinking of the right way to describe what I'm seeing in my head, lol.

Even with the humidity being so high, having air blowing in from outside is going to dry out the tank, likely more than you think it will. Circulating the air that is IN the tank is, IMO, a better way to go.