Swimming pool filters are an essential part of your pool maintenance. They filter out fine particles and dirt to ensure that you are swimming in crystal clear water, day in and day out. Choosing a filter can be confusing because there are several different types on the market. The three basic kinds of pool filters are sand filters, cartridge filters, and diatomaceous earth (or DE) filters. Below is an outline of the different choices on the market and the benefits of each. Hopefully, using this information will help you choose the best option for you and your family.

Sand Filters – Sand filters use a specially graded sand, or a similar synthetic alternative, as the filter media. The water enters the tank and travels down through the bed of sand. During this process, the dirt and debris is 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 filter out debris down to about 40 microns in size. These are great for pools with light to moderate use that do not receive a large amount of dirt and debris. To the right is a brief demonstration of how sand filters work.       Edit:  There are now alternatives to filter sand.    Replacing the filter sand with half as much Z-Media (a type of volcanic ash or synthetic volcanic  ash product) can bump up the effectiveness of sand filters to filter debris down to 4 microns,  now making this type of filter the best of these 3.

Cartridge Filters – Cartridge filters use a paper-type cartridge as the filter media. They filter down to approximately 40 microns, making them basically equal in capabilities to a sand filter. Cartridge filters have, in the past, had a bad reputation.  They were considered hard to maintain because of the need to clean and change the cartridge frequently. However,  manufacturers have recently come up with new filters that have increased surface area and only need cleaning once or twice each year. This actually makes the maintenance issue a positive aspect of this type of filter. Replacement filters are readily available and easy to change.

DE Filters – DE filters use diatomaceous earth as a filter media. The DE filter has plastic grids covered with a plastic type of fabric. A layer of filter powder (Diatomaceous Earth) covers the grids and filters. Diatomaceous Earth is a porous powder with microscopic openings. When magnified, it looks like tiny sponges. Water passes through the DE and debris down to 5-8 microns is filtered out. The DE is finer than sand and is, therefore, able to filter much smaller particles from the water. Because of this, DE filters are considered the best type of filter by most pool professionals. If you want top of the line filtering and crystal clear water, you will want to choose the DE filter.