<a href=showthread.php?s=&postid=9061324#post9061324 target=_blank>Originally posted</a> by stony_corals
Because downdrafts suck A LOT of air in, you should have a gate value on the air intake, that will help you dial it in much better. I run a flexible air hose off my ETSS' connected to a gate value, and it's really easy then. I know some run them wide open, but with a really powerful pump, you'll get a few intermittant large bubbles in there.
I've long been a downdraft fan they are very efficient and effective.