Q&A: Low pressure in return lines and pump pressure is rising quickly after backwashing, help.?

Question by tch: Low pressure in return lines and pump pressure is rising quickly after backwashing, help.?
I have an inground pool with de filter. It has been manually cleaned twice this year. However, there is very little pressure in the return lines, and the pressure on the pump rises very quickly, even after backwashing. Would that be caused from a clog somewhere in the return lines, if so, how would I find it and safely clear it?

Best answer:

Answer by Mike M
Probably not from the way you’re describing it. If there was an obstruction in the lines, you would notice it as soon as the pump was turned on. (it wouldn’t rise quickly, the pressure gauge would most likely start that way.)

[An easy way to test this is if you have a multiport valve on you filter, turn the pump off, and move the valve to the “recirculate” (or sometimes “bypass”) position. Turn the pump back on: if the problem is gone, it’s your filter.]

A more likely cause is that the filter elements need to be soaked in a cleaning solution. Eventually, manually cleaning or rinsing off the elements just doesn’t do it anymore. The cleaning solutions are an acid and a detergent base (usually in a powdered form that is mixed in water) to eliminate calcium deposits and oils that may be clogging up the elements (and should be readily available at pool supply stores. (Don’t use muriatic acid alone; if you must use muriatic, soak the elements in a liquid detergent solution first to remove the oils, then use the muriatic solution. Each should be soaked for at least a few hours, or better, overnight. The cleaning solution combines these two steps into one.) This normally should be done at the end of each swimming season, or twice a season when using Baquacil-type sanitizers. (Since they have a tendency to gum up DE filters.)

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