Fan placement in stand

SpikesReef · Mar 9, 2016

I'm building a stand right now and I have a 3" IceCap smart fan that I want to install into the back wall.

Should I position the fan facing outwards so it pulls air from inside the sump and sends it out?

Or

Should I have the fan pulling fresh air into the stand ? If so would I need to put a vent in the stand somewhere?

143MPCo · Mar 9, 2016

IMO, an optimal configuration would have you using two fans, one pulling in fresh air and one exhausting stale air out.

SpikesReef · Mar 9, 2016

I have doors on the front and the sides. Do you think this would be effective if I placed both of the fans on the back wall? (One pulling air in from outside the stand and one sending air out of the stand)

143MPCo · Mar 9, 2016

Yes as long as you can get to them from time to time in order to clean the dust off and replace when they break down and stop working.

AZDesertRat · Mar 9, 2016

Draw cooler, dryer air in with the fan and exhaust warmer damp air. I would place the fan down lower and exit holes of at least equal size to the fan so you also take advantage of natural convection even when the fan is not running.
Fans get pretty nasty and need frequent cleaning when they are pushing damp air out of a stand or canopy but go a long long time when moving the room air into the stand or canopy.

redfishbluefish · Mar 9, 2016

I must respectfully disagree with those above who state putting one fan blowing IN, with one fan blowing OUT. That arrangement is only moving the volume of air of one fan. Pick a direction and put all fans in that direction.....with the stand ventilated (a hole somewhere.) I'm not sure I agree with @AZDesertRat logic. I would think room air would be "dirtier" than stand air, with all the suspended dust and dander floating about. Either way, those fans will need at least a yearly cleaning. I look at direction as a flip of a coin!

Feltman · Mar 9, 2016

A simple dust mesh screen on outside of fan and all fans blowing in so that the humid air isn't going through fan and dust isn't being drawn in. Clean regularly.

AZDesertRat · Mar 9, 2016

Stand air is very humid so gums fans up quickly. I haven't cleaned the 4" fans in my canopy for 4 years and they still run like new. With my older canopy and fans blowing out I was lucky to get a full year out of the same Vantec Stealth fans even with frequent cleaning.
I had a huge write up on fans and fan placement on a local reef forum but the site is down now and I don't have access to all the data again. I research and document everything I recommend, its not just opinion. I used digital thermometers, a dB meter for noise and whever I had available at the time.

redfishbluefish · Mar 9, 2016

Sounds good.....I'm buying it now.....but, with multiple fans, ALL fans blowing IN.

jsker · Mar 9, 2016

Vent the door and have the fan in back, pulling out the air. If you had overlay door with ero hinges, there would be enough gap around the doors that you would not have to vent the doors.

AZDesertRat · Mar 9, 2016

All fans blowing in as long as you have at least equal sized exit holes or area for the air to escape. If you don't provide a way for the air to get out you build up head and the fan performance suffers. It doesn't take a lot of fans or massive velocity if the air can move freely, 4 or 5 air changes a minute usually works great.
My canopy is roughly 10 cubic feet of volume and I have two 120mm Vantec Stealth fans, one in each end down low and four 120mm exit holes in the top center of the canopy as far from the fans and as high as possible. The fans are powered by DC variable voltage power supplies so the speed can be controlled so at 100% speed they do 10 complete air changes and evaporate too much water, at 7.5 to 9v DC they are completely silent and move around 5 canopy volumes which allowed me to sell my 1/4HP chiller and still keep the display at 78-79 degrees in the peak summer months using 2x250w MH and 2x140w VHO actinics.
After switching to AI Sol Blue LEDs the fans never run anymore. They are temperature controlled using my RKL controller.

143MPCo · Mar 9, 2016

Fans are cheap, relative to the overall expense, pushing or pulling, or a combination thereof, either works, the important part is ventilation.

CoralNerd · Mar 9, 2016

I had Melev's Reef make me a custom fan tray.
It has a spot for two fans and the fans blow air down into the sump.
Works great and looks cool.

Gamma · Mar 9, 2016

Would love to see some pics on how everyone has fans placed on sumps.

Chris155hp · Mar 10, 2016

Following

AZDesertRat · Mar 10, 2016

My sump is hidden under the stand so I used a WalMart clip on 2 speed 6 or 7" fan on low speed clipped on the side so it blew across the longest surface width wise. More efficient than straight down as it contacts more surface area. Kind of like the wind blowing across a lake.

s2nhle · Mar 10, 2016

I had my fans flowing across my DT last summer. It did help cool down the temp.

Jwalker814 · Mar 10, 2016

Just curious to theory behind venting the sump. That tends not to be your heat source as you lighting tends to be your main location of heat. As well as the top of ur DT should have the most gas exchange besides the return into the sump.

My vote, a single exhaust fan in the top of a hood is better than a series of fans for a sump.

I had a 5° drop by adding a single 250mm PC fan exhausting my canopy. I chose a PC fan because they tend to be quite and extremely efficient in air movement.

Your sump can be vented enough with an open back or vent holes or other venting fixture for natural air movement throughout the sump.

CoralNerd · Mar 10, 2016

I always thought I would have more heat above the tank with the lights but surprisingly it was in the sump. A lot of tanks now a days are open top and run by leds. The sump has so many electrical blast and what not it's easy for it to generate heat. I think the best fan placement is actually both above the tank and also in the sump. I set my apex to turn one set of fans on in the sump and when it gets hotter I have a stronger, noisier fan kick on above the tank. Good luck and stay cool. [emoji475] [emoji106] [emoji111]

SpikesReef · Mar 10, 2016

I'm going to have a floating canopy that's low profile. Also I am going to run a reverse light cycle on my refugium. The stand will be caulked and painted with kilz2 + appliance epoxy. I expect the head to build up from the closed atmosphere with the light. I plan to mount the fan on the back wall just above the sump in line with the fuge. This will dissipate where I expect the main source of sump heat to come from. I will take the front door off at night as light bleed won't be an issue. Thanks everyone!