Venting stand- fan suggestions? passive venting?

[reefinmike]

Hey all,

I'm in the process of finishing off my new system build and could use some advice regarding venting. The system is pretty darn quiet as it is but I would like to make it even quieter. A computer fan on each end is not an option. The system is a 90 gallon with a 55g sump. The tank has glass tops, the right side of the sump is completely covered by glass and I intend to get some glass cut to cover about 50% of the left side mainly with the intent of quieting the air intake. The tank runs at 79 degrees and only about a half gallon of water is evaporated or skimmed out per day.

The left side of the tank faces my living room and the right side is pointing down a hall. My refrigerator is on the opposite side of the wall behind the tank. I'm thinking of having a downwards slatted hvac vent cover on the right beneath the apex stuff so that fresh airflow goes past the electronics(which I will eventually shield with thick plastic). Initially I was planning on putting a computer fan on the left behind the skimmer and exhausting straight through the wall to the area behind my refrigerator. Then I had an Idea- Heat rises so would it be feasible to forgo the fan and use the drywall cavity to draw up the warm air? I could cut a large hole behind the skimmer and on the other side of the wall I could cut out drywall near the ceiling and screw in a hvac vent cover so it looks pretty? Would the humidity be too much for the drywall? I realize nail pops may be a possibility but that wouldnt bother me as the majority of the wall is behind tank or fridge. If this method of passive cooling would work but cause too many issues with the drywall, I could create a wall cavity sized air duct with thick plastic and heavy duty duct tape.

If a cooling fan is the only feasible option then I would like some suggestions on the quietest appropriately sized fan.

Thanks for any and all input!

 

[mcgyvr]

From what I see you are certainly going to have humidity issues..
I would put the vent on the right side and a fan on the left side blowing in..

Something around 30-50cfm should be plenty... but I can't tell if that picture is showing your entire sump area or not.. Thats really tight in there..
You can get many "silent" fans in the ~20db range for like 10-15 bucks and be done..

 

[reefinmike]

mcgyvr- thanks for the input. Having a fan on the left side of the stand is not an option due to light spillage and the fact it opens up the living room to all the noise of the sump which is the main point of enclosing the otherwise beautiful sump. Also, wouldn't it make more sense to have fresh air going past the electronics first and have warm humid air from the sump blown out from the stand via a fan on the left side(where the wire rack is) blowing through the wall to the other room? I would create a fan sized wood box going directly through the wall so the fan isnt dumping humid air into the wall cavity. I'm aware that fans work better facing one way or the other but I'm prepared to buy an extra $10 fan to have on backup.

Also-does anyone know of a variable speed fan that is compatible with my apex VDM?

 

[mcgyvr]

I'm sorry.. I confused my left and right.. Its amazing I put shoes on in the morning..

Vent on left.. fan on right.. enjoy..

 

[d0ughb0y]

I researched and analyzed stand venting when I built my stand.
I eventually followed the design of red sea reefer stand (very well thought out design imho). It uses passive venting.

The stand has a small gap between the base shelf (where the sump sits) and the door. This is where the air is sucked in.
Then at the back of the stand, right at the very top there is a cutout for warm air to escape.

in your picture, I see the left,back and right all have no holes or any kind of opening.
I think passive venting will work only if the opening is at the very top edge of the stand. since I see 2x4s, your only option might be to use a fan.