When choosing the best pump for your pond calculate your head loss. Head loss is the vertical distance the pump has to push the water plus the friction caused by the water flowing through the pipes and fittings. If the flow rate is too high for the pipe's diameter, you create more pressure. Head losses also happen when filters clog with debris and create back pressure; this can be eased by keeping your filter clean. Too many elbows can add to back pressure. Pumping vertically, whether it is to a waterfall or a filter, will also increase head pressure. Running costs increase with head loss, so it is important to keep head loss to a minimum.
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