Six-inch ducting problems

I have a 1000 watt light with 6-inch ducting fittings. I bought the ducting without thinking about vents.

I was thinking of something like: http://www.google.com/products/catalog?hl=en&q=6''+vent+exhast&gs_upl=658l2201l7l2775l11l11l0l0l0l0l189l1500l0.11l11l0&bav=on.2,or.r_gc.r_pw.&biw=1920&bih=977&um=1&ie=UTF-8&tbm=shop&cid=2257622187717391740&sa=X&ei=ZqhzTqj8GYXPiALDyNGzAg&ved=0CIkBEPMCMAE

No one here has anything like that. Not Lowe's, not Home Depot, not the local hardware store and not at the hydro store (who sold me the exhaust fan and ducting). Home Depot and Lowe's have similar four inch vents and have 6 to 4 inch reducers.

Am I not looking hard enough?
Am I going to have to use a reducer?
If I reduce it two inches how much air flow will I lose?

Are you worried about bugs and stuff? Can just put a screen. But I use a 6" to 4" reducer and it seems fine, then again I haven't scientifically proven it with an airflow meter or anything.

i would not recommend reducing. HD and Lowes just dont have them all the time. its stupid. The one you posted would function much better than reducing.

chasmtz said:

i would not recommend reducing. HD and Lowes just dont have them all the time. its stupid. The one you posted would function much better than reducing.

Click to expand...

Do you have anything to back up this recommendation? Not trying to be confrontational but if its over a short distance and the reducer is going to be right before the vent then I cant see how it would affect it much at all.

Ya lowes and HD suck donkey balls for having a good selection of vent adapters.

As far as a solution.... Good luck, I havent seen anything bigger than 6" on that stuff. And no i wouldnt reduce it to 4"

I'd be interested to know, if anyone has an air flow meter, how much a 6 in to 4 in reducer reduces an in-line fans' CFM. Any input on the matter is greatly appreciated.

my grandfather and father are both retired sheet metal workers. I have a certain amount of knowledge and informational resources to know ducting well. Reducing is just that, a"reduction" in air flow. I recommend not doing that. Also, its common sense