Pond is 20 yrs old and gets oak leaves for its nutrient. Body of water is perfect bowel shaped 130ft across and 35ft deep at center. I figure I have 1,466,000 gallons in my aquarium. Have problems with filamentose algae that I fight with chemicals. Have a fountain in the middle that runs spring to fall and a dock deicer at surface of water that shoots aerated water up a foot June through August both devices run 24hrs a day. Only thing I know about aeration is what I have read on this fantastic forum. Want to get away with dock deicer and aerate under water to help in muck control and provide a water exchange to make a deeper oxygen content. At 30+ foot depth I am pretty sure I have a thermal layer but on cooler overcast days it has turned over and killed my fish thus the dock deicer to at least put oxygen at surface. I have purchased a used Gast 0523 rotary vane pump that puts out 4CFM with 10 psi max pressure. I hope to run 1/2 ridged pipe 50ft from shed to water then weighted flexible hose to a twin stone Airmax Proair placed at 15 foot depth. Is the single twin stone Airmax enough in one location? Am I putting the aerator too deep? I do know from this forum I should monitor when first installed as to not get a quick turnover and kill fish. Thanks for reading my ramblings.

Welcome CW from another Missourian! I did some time near St Charles as a kid.

It sounds like you are on the right track with your aeration design. I do not know anything about the Airmax Proair diffusers. So, I would want to check with the manufacturer to make sure that the diffusers can handle the CFM from the pump (what are the diffusers rated for?). With your diffuser at the 15' depth (good choice for a 35 foot deep pond), your pump will see about 8 to 9 psi. This should yield just under 4 CFM to the diffusers. If your diffusers can not pass the 4 CFM, your pump will work extra hard and have a shorter life. I would balance the number of diffusers with the pumps output even if that means more diffusers which would allow for multiple locations. For example, if the diffusers are rated for 1 CFM each...you would want 4 of them. You should also ask the manufacturer if they have any lift rates charts available (how much water will a single diffuser move per hour). You want to make sure you are turning over the whole pond at least once daily according to minimum popular opinion. I like to design so that it turns the pond over at least once in a 12 hour period in case you need to run only at night to keep pond water temps down in the heat of the summer.

Also, consider putting a base under your diffusers to get them off the very bottom of the pond. Mine are on 3 foot tall stands and I think I am still pulling up sediments and making my water look muddier than it should. The jury is still out on this, however.

The larger pipe and weighted tubing you run, the better the system will flow and the less the pump will have to work. I would consider running 5/8" ID PEX to the pond and 5/8" ID tubing to each diffuser, but 1/2 inch will work if you keep the runs short.

Let us know what you find out from your diffuser people and get back to the forums. Here is your pump curve for future discussions...