Venting canopy and cfm turnover rate.

[CAreefer]

Hey all, I'm in the process of planning cabinetry for my 225 gallon mixed reef tank. The question I have is how many times an hour should I turn over the air in the canopy to keep 750-1000 watts of metal halide cool? I have the luxury of being able to vent the canopy out into the garage and am thinking about using bathroom exhaust fans mounted high on the wall to pull air into the garage. The cabinets will be floor to ceiling and sealed to the wall. I am going to put fresh air intakes at ground level with the hopes that this will ventilate the sump area as well. I have planned the stand structure for a 6" air gap in the back and right end between the tank and walls. I have roughly 120 cubic feet of air in the cabinets. The fans I am looking at are rated for 70 cfm and I'm thinking of running 2 of them centered on the outer metal halides. Any thoughts?

TIA
CAReefer :eek1:

[Nagel]

Way overthought I think, heck, I never even considered CFM.. I run 1200w of halide and 820w of VHO on my 300 with just a "vent booster fan" hooked up to some neat ventwork in my hood that exhausts it out of the house... I'll see if I can find the CFM for that fan, but its certainly nothing fancy or high powered...

the two fans you are thinking of will turnover the cabinet every minute, so as long as the hood section is even somewhat sealed, I think you will maintain the cooling you want, may even get some excess evaporation (which is always a good excuse to add more kalk with your FW topoff hehe)...

[Ken Sellick]

Two thoughts , Venting into the garage is ok if you are in a dry climate. If you are in a moderately humid reigon it is better to vent directly outside to held prevent mold in your garage. Mold is becomming an issue in public schools and residences in the northeast.
If you plan on having you air intakes at low points in the room it's a good idea to put air filters inline. Air that is low to the floor has more stuff in it like houes dust and animal fur.... Simple furnace air filters work fine for this.
I am currently reasurching CFM volumes for the system I am designing. My current plan is to use (10) 400w MH with actinic suplements. I'll try to get back to you when i have more info on CFM.

[CAreefer]

Thanks for the info Ken, I do plan on using filters on the intake side. I do live in a dry region and mold/mildew is not a concern. If it does happen to become a problem, then a couple elbows and some more vent pipe and problem solved. I am considering at this point making an inline box to house a couple replaceable 5" box fans, as my research on bathroom fans shows poor movement/cfm rating on most. I can get the sace cfm from a basic 4" muffin fan and is considerably cheaper to run and less noisy. Although noise isn't really a concern since the fans will be remotely located in a garage cabinet.

Thanks again
CAReefer