No matter how diligent we may be with our pool cleaners, dirt, debris, and other unsavory bits in our pool water can elude our pool cleaning devices. Luckily, pool water gets pumped through the pool’s filter system where particulates in the water become trapped. A swimming pool’s filter system is an essential component for maintaining clean, safe water. What type of filter system does your swimming pool use?
The three existing types of swimming pool filters are Sand Filters, Cartridge Filters, and Diatomaceous Earth Filters (DE Filters, for short). Here’s how they each work:
Sand filters, often considered the easiest filters to own and maintain, use a specially graded sand as the filter media. Water enters the tank through a diffuser. As the water goes down through the bed of sand, the dirt and debris are trapped between the grains of sand. When the water reaches the bottom of the filter, it enters the laterals and is returned to the pool. Sand filters trap debris as small as approximately 40 microns in size. Anything smaller than 40 microns will often pass through the filter and get circulated back into the pool.
One of the most popular choices among the filter systems is the cartridge filter because it can be removed and cleaned with out backwashing, which saves pool-owners time and energy. Cartridge filters use a paper-type cartridge as the filter media. They do not filter as finely as DE filters, but they produce about the same water quality as sand filtration. In the past, cartridge filters were considered a nuisance to maintain, but over the years, manufacturers have developed newer filters with enough surface area (300-500 square feet) to require cleaning only once or twice each year.
Diatomaceous Earth (DE) Filters
DE filters are the most effective of the three filter systems. Diatomaceous earth comes from a naturally occurring sedimentary rock that crumbles easily into a fine powder. The DE filter has plastic grids covered with a plastic type of fabric. A layer of the diatomaceous earth filter powder covers the grids and filters the water. As the water passes through the filter powder, any debris down to 5-8 microns is filtered out. Because the DE is much finer that sand, it is able to filter much more effectively than a sand filter or cartridge filter.