Actually many of the rubber membrane diffusers will work with very little air volume for example 0.1 or less cfm providing the psi is adequate to force air out at a depth. HOWEVER we need to define what we mean by 'work'. Just because a diffuser is producing a few or several small bubbles per second does not mean it is adequately mixing a volume of water. My windmill during a slow 4-6mph wind will produce a scant number of bubbles that results in little if any water upwelling. For a diffuser to be working to mix a water column it should be producing several thousand or 100,000 thousand bubbles per second not just several or a few hundred bubbles per second. The Basic Aeration Rule is: the more bubbles produced and the smaller the bubbles the more water that is moved.
There was aeration discussion on this forum recently that discovered (Ted Lea) the Vertex diffuser had a unique or special built-in valve that allowed the air to be balanced or evenly spread among paired or multiple diffusers so each diffuser received equal amounts of air allowing the entire multiple diffuser head to produce an even bubble pattern. To operate this special valve each Vertex diffuser required at least 0.5cfm.
Last edited by Bill Cody; 09/30/14 04:20 PM.
