High swimming pool filter pressure is usually the result of a lot of particles being filtered out of the swimming pool water. When pressure rises it is time to backwash the filter if you have that option with a sand or diatomacesous earth (DE) filter. If you have a cartridge filter it is time to disassemble and clean it.
Note: if you have a DE filter that has not been fully disassembled and cleaned recently you may need to have it fully disassembled and cleaned as well. A tell tale sign is if you find a backwash only buys you a few days time before the pressure is flying back up again.
Also Note: DE filters offer the best swimming pool filtration available (4 microns or less) but can get in a “feedback loop” to use a musician phrase if they are filtering really well or for more than a day at a time without a break.
Basically what happens is the particles they filter out cause the DE filter to filter even better… then the DE filter filters even more particles out increasing its filtration even more… next thing you know the filter breaks its internal parts and starts leaking or blows open the top of the case!
Because of this it is helpful to give a DE filter at least 2hrs off out of every 24 hour period. This allows the DE to fall off the grids and when it comes back on and re-coats the grids it won’t have a “sheet” of superfine debris covering the “blanket” of DE on the grids. If the gauge reads normal but the water stays dirty, test whether the filter is working at all.
