Pond Boss Forums AERATION Systems questions Areation questions

To tell you how much air you need to turnover this pond you are not providing enough basic info for me to do the estimates. Needed: A. air flow of pump in cfm which has some to do with the hp.
we will assume diffusers are at 15ft deep (~7.5psi). You say you want to use two membrane diffusers. How big (dia) are they? Are they disk, tube, or homemade? What are the pore sizes of the holes / slits? Some brands are better than others. They are all factors.

I can tell you that for 4cfm, 4 diffusers ganged together with 1cfm going to each or all 3.5-4cfm to the 'gang' will turn over the 0.66 ac pond two times faster than 2 diffusers. Some diffusers will operate well with 0.5 cfm which means if your pump produces 4cfm at 15ft deep you could operate 6-8 diffusers, not just two. Putting too much air volume into a diffuser expands the slits / holes larger and this lowers the efficiency of the diffuser.

If you are really interested in efficiency use 4 diffusers instead of 2. A gang of 5 vertex 9" dia disk diffusers using 4 cfm will turnover your pond once every 2 hrs. Thus 4 hrs of pump run time a day should be all the aeration your pond should need daily Apr-Nov. Your GAST compressor if in new condition and well maintained should then last a minimum of 15-18yrs on the first set of carbon vanes. However you 'smoked' your compressor once by not having a pressure relief valve, so my estimates don't mean much.

I also rebuild GAST pumps. If the pump is maintained properly and the diffuser is sized properly for the pond size and volume where it does not have to run 24/7 your GAST pump should last 20 years not 2! My rotary is 18 yrs old on the 1st set of vanes. The vanes have a typical life span of 10000 hrs at 10 psi; comparatively longer if pump runs less than 10psi. Motor bearing standard life is 30000 hrs and longer when not running at 10psi. Normally you should go through 3 sets of vanes before the bearings go bad assuming GOOD maintenance. Believe who you want.