Pumps By Flow
A good rule of thumb for small ponds is to turn over the full volume of the pond water twice every hour to ensure proper circulation and help buffer water temperature fluctuations. Your filtration system, waterfall height, hose lengths and diameters and plumbing components that are to make everything operate properly will consume a portion of the pump's overall flow. The rated flow of a pump is often with no restriction and shows the gallons per hour or liters per hour of the water as it comes right out of the pump. Any given tubing system, plumbing fitting elbows or tees, filters or opening that water moves through or around creates a drag. Frictional loss measures the amount of water flow rate lost to drag. Static head refers to the distance between the pond water surface and the highest point to which the water is lifted. These two factors added together create the total dynamic head and the final tally of total dynamic head that you measure directs you to select a pump often with with a flow rate greater than you might presume. You can restrict an excess flow, if desired, but you cannot make a pump deliver a higher flow rate than its capacity.