Here is a performance curve for a Hako linear 100 LPM pump, which should be similar to my Pondmaster AP100's (Pondmaster does not provide a performance curve for their pumps
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It will give you an idea of the drop off of air flow as water depth increases. That is the down side to linear type pumps - performance falls off with depth. The up side is they are VERY energy efficient and low cost and as long as they are used within their capabilities can operate at very low electrical costs.
performance curve of a 100 lpm pump The jury is still out if overall these pumps will be any cheaper to operate in my pond than a more conventional rocking piston or rotary vane pump over say something like 5 or ten years. The electrical cost should be far less. But my maintenance and capital replacement cost do to shorter life of the pumps may eat the electrical savings up. We will see.
