My new pond is clearing up nicely and I'm shopping aerator systems. I'm getting some different sugestions from the two pond shops near me. My pond is 120' x 60', 6' to 7' deep in the deepest spots. The pond is kind of figure 8 shape. I'm planing on two diffusers. One shop is recommending a 1/8 horse diaphragm pump the other is recomending a rocking piston style. I want to buy a whole system with case. Any sugestions? Is the diaphram setup what I need?

Thanks

Based on my recent research, a rotary vane pump gives you more air flow for the same horsepower. The down side is they don't produce very much psi compared to rocker pumps.

Figure .5 psi per foot of water depth. I added another 1 psi for the diffuser resistance, I was probably over estimating. Anyway, diaphram pumps run out of psi pretty quick.

My gast rotary vane pump will produce up to 10 psi. About double of what the diaphram pumps I looked at did. The rocker pumps create even more psi, so that is not a problem. I have heard that they make more noise than a rotary vane though.

I have used both types and now run a 1/4 hp Gast pump and two 9" Matala Diffusers> Does a good job consistently, in a similar volume and deep pond. Purchased from Keystone Hatcheries - great group and very helpful.

The 1/4hp Gast rotary is your best compressor option for this small pond. Use one or two disk membrane or 24" tube diffusers and in MI you would only have to run it 3-4 hrs per day May to November. Keep the pump dry and well ventilated so air can circulate around it to remove heat and it should last you at least 25-30 yrs.