My pond is about 17' at the deepest something around 1/3 acre, and I'm looking for the most efficient pump to prevent muck buildup. I'm hoping to avoid having to go to a full 1/4HP 300W+ pump.
I'm looking at the Hakko 120L which has a shutoff of 18'. I'm thinking of running my pumps at about 13' of depth where the airflow is rated to 2.6 cfm. I think I would have to use 3/4" tubing to reduce friction because I'll be dealing with 200-300' of tubing in total. I don't even think 5/8" gets the job done. With 3/4" tubing width I would lose about .15 psi. Plus .15 psi for each of two diffuser s(Matala has the lowest back pressure I think). So the system should lose less than .5 PSI if I built it right. That would bring my cfm down to around 2.4-2.5 which should still leave 1.2 for each diffuser. It's close but if I had to I could always move them up to 11-12' which is still deeper than 90% of the pond and assume there would be some mixing below this depth still.
One concern is that this would affect the life of the pump or the pump would weaken over time. I know JourneyMan runs his HiBlow 120L at 9-11' of depth, which is deeper than what that pump is rated for (4.3 psi). The Hakko doesn't seem to come with a maximum continuous operating PSI, it just says that it shuts off at 18' and is "Ideal" for 4-12'. I would be just outside that ideal range at 13' but well below the shutoff of 18'.
My other concern is that this is all for nothing because the pump could consume more energy than it is rated for due to the higher PSI. Does anybody know if linear/daiphragm pumps use a lot more power than what they are rated for? When they say the pump uses 126W, what depth is that at?IF this is successful it could be a good more economical system for many on here since it would work down to 12-13' for two diffusers or 14-15' for one diffuser. The pump costs less and the electricity savings could be $100-200 per year vs a gast 0523 550W pump. The big costs is the 5/8" - 3/4" tubing.https://www.hakkoairpumps.com/subcat12.html