Blog | What you Should Know About Swimming Pool Filtration.

There are three different types of swimming pool filters. They are the Sand, Cartridge and Diatomaceous Earth commonly known as D.E. They all will clean your pool water but they are not all equally good at it. We will start with most common filter used - the sand filter.

In Tulsa, sand filters are the most prevalent type of filter used. The main reason is the ease of use for the homeowner and secondly they are the least expensive choice for pool builders to purchase. Basically they work by water passing through a tank "filter" filled with silica sand. The water passes through the sand and the particles of dirt get trapped in the sand. There is a pressure gauge on top of the filter that tells you what the pressure is. As the sand collects more and more dirt the pressure rises. When the filter is dirty you turn a valve on the filter and backwash the dirty water out. Usually about a minute and a half. Then you put the valve back to filter and the process starts over. Although these filters are the most common they are the least effective. They only trap particles of dirt down to around 20-40 microns. One micron equals one millionth of a meter or approximately 1/25,000 of an inch. The diameter of a human hair is around 70 microns and the visibility limit of the human eye is about 40 microns.

The next filter we will look at is the Cartridge type. It has cartridges inside it that the pool water passes through and traps the dirt. This type of filter is used in parts of the country where water sources are limited, such as parts of California and Nevada. This being due to the fact that this filter is not back washed. Therefore you don't waste any water. The way this filter is cleaned is by disassembling it and hosing off the cartridges. Then reassembling it and starting the system up again. It filters particles of dirt down to a range of 10-15 microns.

Lastly we will look at the Diatomaceous Earth filter, D.E. This is the best filter for sparkling clean water. But as usual being the best it is also the most expensive to buy. This filter has grids inside it that are coated with D.E. powder. D.E. powder is fossilized exoskeletons of diatoms. The water passes through the coated grids and they catch the dirt. This filter will capture particles of dirt down to 2-5 microns. There is no better filter for swimming pool water clarity. It is similar to the sand filter in that it also is back washed when it gets dirty. Even though the D.E. filter is back washed like a sand filter it is back washed less often. Where in some instances sand filters are back washed on a weekly basis D.E. filters are back washed on a monthly basis or longer schedule. After a D.E. filter is back washed you will need to re-coat the grids with D.E. powder. This is done by pouring D.E. powder into the surface skimmer. It then is pulled by the pool pump directly to the filter and coats the grids. It is now ready to filter again.

It may look like there is very little difference in the three filters. But I can tell you if you had a swimming pool with a D.E. filter and your neighbor had a Sand filter. A person that knows nothing about a pool could fly over in a helicopter and tell which one has the D.E. filter. It is that obvious the water just sparkles.