Sand filters are the oldest form of filtration for a swimming pool. They consist of a large spherical-shaped globe that contains silica sand (may be referred to as simply ‘filter sand’). As water flows into the filter it passes through the sand. The dirt and other particles become trapped in the sand allowing clean filtered water to return back into the pool. Sand filters remove particles as small as 20 microns. The filter sand can last 5-10 years between changes giving you a very economical filtration system.
Backwashing a sand filter system is part of the regular maintenance of the system. As particles become trapped in the sand it restricts the water from flowing back to the pool. Your pressure gauge will start to increase as the filter sand clogs up with dirt and debris. This is your signal to perform a backwash. Backwashing will send out the dirty water through another port on the valve usually labeled “waste”.
Cartridge filters consist of a simple 2-piece tank (lid & bottom) with a cartridge inside of that tank. The cartridge is very similar to the air filters you can find in your car. Water is pushed into the tank from your pump and flows through the cartridge membrane. Particles and debris are trapped in the fabric and clean water returns back into the pool. You can expect the cartridge to filter down to about 10 microns.
Cartridge filters require very little maintenance, which is a huge pro for this type of above ground pool filter system. When the pressure gauge reaches 10 Psi above it’s normal reading, it’s time to clean the cartridge. You should remove it from the tank and hose it down thoroughly with your garden hose. Backwashing is not necessary with cartridge filters, eliminating water and chemical loss. The cartridge inside the filter will usually last about 1-3 years before needing to be replaced.
Cartridge Filters are a great choice for Above Ground Pools
Although they both have some advantages, a cartridge filter would be your best choice for your pool’s filtration system.
A sand filter will only filter down to 20 microns while a cartridge filter will filter down to 10 microns, half the amount. This means that a cartridge filter system will be able to rid your pool of more particles (dirt and debris) leaving it cleaner and more sparkling. Having a cloudy pool will be a thing of the past.
The maintenance of a cartridge filter is much easier than a sand filter. Performing a backwash on a sand filter (part of the regular maintenance) will take you about 20-25 minutes. Cleaning off the cartridge should take only 5-10 minutes. Backwashing a sand filter will lower the water level of your pool and you will lose some of your chemicals along with it. You will need to slightly fill your pool up again and will need to rebalance the chemicals. In other words, more maintenance will be required for a sand filter.
When it comes time to close up your pool for the winter, all filtration systems should be drained, cleaned and brought inside somewhere where they are not exposed to the elements. They are made of plastic so the freezing temperatures can cause the filter tank to crack. Brining your cartridge filter in for the winter is an easy task being that it is very lightweight. Any adult or teenager would be able to do this without any help. On the other hand, a sand filter may have anywhere from 100-250lbs of sand inside the tank. Moving it to an indoor location usually requires more than one person.