Suggestions above are good.
Ideally you want the dual or multiple diffuser heads (membranes or stones) close enough together so the rising columns of water quickly merge together that produce more upwelling than if they were working separately. Manufactured company systems incorporate this philosophy; hopefully all by testing. Merged columns work together(team) to gather more rising water. Thus a combined rising column moves more water than two single rising columns. This assumes that in each scenario all heads receive the same volume of air(cfm).
Also, if you double the cfm(2cfm) to one diffuser instead of splitting 2cfm into two diffusers (1 manifold) the dual manifold will move more water because the single diffuser(2cfm) has the rubber membrane pores stretched further open that creates larger bubbles. With any cfm, smaller bubbles more water than larger bubbles mainly because the smaller bubbles collectively have more surface area that creates more upward moving water. Each type of diffuser has an optimum air flow for optimum efficiency.
RULE: The smaller you make the bubbles (same cfm) and more bubbles you make - the more water you move. Example: A 'large' 20mm bubble has the surf area of 12.5cmsq and a vol of 4.19cubic cm. 296 3mm bubbles can be made from this 'large" bubble. These 296 bubbles have a total surface area 83.6cmsq which is 6.6X more surface area of our 'large' bubble. In theory we move around 6.6 times more water with the 3mm bubbles than 20mm bubbles; all assuming same cfm. IMO the best membrane diffusers are designed to make 1mm bubbles at optimum air flow volume.
Last edited by Bill Cody; 01/08/20 11:47 AM.
