Filter Pressures - Sand and DE

High pressure, as measured by the gauge atop your filter is not a good thing. It does not represent good water flow, just the opposite: high pressure indicates increased restriction to the flow of water. When the filter's pressure is substantially higher than it was when you last backwashed,then it is time to backwash again or to perform a clean out. Sometimes, the clean pressure of a swimming pool's filter will be as low as 5 to 6 pounds per square inch (psi), other filters may range up to 20 psi or more, clean pressure. It just depends on a pool's particular configuration. The power of the pump, the size of the plumbing, the size, type of filter, the water inlet/outlet orifice size, the distance the pool is from the equipment, and any add ons like suction or pressure side cleaners, all influence the PSI as read from the filter's pressure gauge. All of these items have an impact upon what the pressure will be.

How are you to determine when the pressure has risen high enough, to cause you to backwash or clean the filter? There are several different ways of determining this. The first is when you notice that the "action" on the pool's surface is beginning to slow down, you may notice for instance that the inlet jets don't seem to be pushing the water as far as before, or perhaps the skimming action has slowed down.

Another way is to put your fingers into the suction line, at the bottom of the skimmer's housing. If your fingers feel like they are going to be snatched off your hand, then the filter can probably go without being serviced yet. If there is not much of a pull on your fingers, then its' time for servicing.

You may notice also, that your suction side or pressure side cleaner doesn't climb the walls as well as before, or starts to let dirt accumulate around the bottom of the pool. Also if you vacuum manually, you may notice that the suction has dropped off and dirt is not being pulled up into the vacuum hose as vigorously as before. Sometimes, if the filter is really plugged, any additional dirt added to it will cause the dirt to just go right on through and and back into the pool via the inlet jets, then you will see the dirt being put back into the pool.

If any of these situations develop, it is time to take a look at the filters pressure gauge. Most of the time you will see that the pressure gauge is 6 to 15 psi over what it was when the filter was clean. As the dirt, dust and debris accumulate within the filter, the pressure will increase and will be measured by the pressure guage in pounds per square psi. Generally, you will not want to wait until the pressure is really high. So don't wait too long. Over time you will learn at what psi pressure to backwash or clean your filter


.