I'm designing the interior of a 100-cubic-foot grow closet. I plan to use a 600-watt HPS bulb inside a DayStar air-cooled fixture with 6" flanges. I plan to use a 6" 300 CFM inline fan to cool the light. And I plan to use an 8" 636 CFM inline fan to scrub the air and ventilate the room. I plan to use motor controllers to dial in the fastest stable speeds for the motors. What type of ducting should I use for quiet operation? There are semi-rigid types that can be bent in any desired direction. And there are light, flimsy types. And there are insulated types. Please advise. Thanks.
insulated ducting... found at home depot or lowes is the cheapest... its like 35 or 40 bucks for like a 30 foot section.... more or less.. i could go look at the box if you wanted to know how many feet it is... its easier to find at lowes than home depot.. you will have to have a sales associate get it down from the depot also.. it appears your going to have alot of air movement... make sure you light trap your intake, which I'm also assuming is passive)
thats a lot of ventilation for a small cabinet. listen to Tihspeed completely right about using insulated ducting. you can also up size the ducting. just use the 8" for the 6" fan. it will help with noise. plus you only have to buy one size. just make sure you use the clamps for it or it could pop off. these fans put a lot of pressure on the lines. he also mentioned a light trap for the intake. this is vital. put a hepa filter over it too. get a larger one maybe 20x25 or so to prevent negative pressure and insure good flow. the hepa filters filter out pollen and mold spores. defiantly a good thing. not to mention dust. it will keep your room much cleaner