There are three common technologies that are available in above ground pool filters. They are the diatomaceous earth filter, the sand filter and the cartridge filter. The design and manufacturer of these filters will generally have a similar appearance, but they are distinguished from each other by the internal media that actually performs the job of filtering the water.

Diatomaceous earth filters, or DE filters, utilize a set of filter elements that are coated with diatomaceous earth. The grids are the supporting structures that hold the media that actually performs the filtering process. Diatomaceous earth particles are extremely small and have the ability to remove microscopic impurities from the pool water. These types of filters are cleaned by either removing the filter elements and removing the impurities or by reversing the water flow through them and forcing the dirty particles off, in a process called back washing. These filtering units are sized by the area of the grids.

As the name implies, sand filters use sand as the filtering media. Sand filters are typically installed in a round housing, and are sized by both the surface area of the sand bed and the engineered flow rate of water that they can handle. Sand filters are an old and trusted technology and are found in many water and wastewater treatment plants. Water is introduced into the top of the sand filter and is sprayed over the sand bed where the cleaning process takes place. The top layer of the sand and the trapped impurities perform the bulk of the filtering process while the level of sand below the top performs the secondary and polishing stages of cleaning. Sand filters are usually clean by back washing them.

Cartridge filters use filter elements to clean the pool water in the same manner that your heating or air conditioning system uses filters to clean the air within your house. These units contain filtering elements that are cylindrical, and they may contain one or more elements within their housing. They are sized by the surface area of the filter cartridge, and since they are pleated they will provide a much greater surface area than the actual diameter of the cartridge would imply.

In order for swimming pool filters to effectively clean the pool water, they will require a turnover ratio of 6 to 8 hours. All pool filters will need to be cleaned periodically, and this frequency can be lessened by purchasing a filter with a higher rating. Diatomaceous earth filters will remove the finest particles from the pool water, followed by cartridge filters and then lastly by sand filters. However, the finer filtering media will offer more resistance (indicated by the pressure drop across the filtering unit) and will require more frequent cleaning to maintain their operation or a higher rated pump. Most owners select a sand filter as their above groun pool filter since they do not require the extra fine removal capabilites of DE and cartride filters, because they have a lower pressure drop across them and because sand is the most economical filtering media.

The repair guy came out and fixed my swimming pool heater. He told me to keep it running for the next couple of days while it breaks in. The problem is that my pool filter system is old and is a piece of crap and I have to keep restarting it. So can anybody tell me if I can turn off the pump and just let the heater run?

The water needs to circulate in order to move it through the required treatment processes. The swimming pool pump is used to do this. In your house, the water flows through the pipes because the pressure or motive force is supplied by the water company by a pump or the pressure created by a storage tank if you are supplied by a water utility company and by a pump if you are serviced by well water. The pool pump serves the same purpose. It provides a suction on its intake side to draw the water into it and discharges with a positive pressure to force the water through the trailing components and reture the treated water to the swimming pool.

After the water is discharged through the pump, it passes through a filter to remove and particulate matter that has settled into the poll. Swimming pool filters generally use sand as the filtering media, although cartridge and grid type filters are also commonly employed. Filters operate by a mechanical action and do not alter the water chemistry, but simply remove the solid impurities.

Many owner opt to install a pool heater to expand their swimming pool season, and this component is generally next in line. Above ground pool heaters are generally use gas, either natural gas or LP gas, as their heat source. However, swimming pool heat pumps are gaining popularity due to their lower operating costs. Electric resistance heaters are not as common as they once were due to the increased cost of electricity. Although solar panel pool heaters offer lower operating costs due to the fact that they don't need an energy source other than the sun to heat the water, they are not as popular with above ground swimming pool owners due to their high capital costs and the space requirements of the panels themselves.

Once the water has exited the heater, it is next passed through the chlorinator for disinfection purposes. Although some form of chlorine can be manually added, an electronic chlorinator automates the process and eliminates the need to constantly monitor the water chemistry and deal with harsh chemicals. Electronic chlorinators also use common salt that is converted to chlorine by the unit to save on operating costs.  This chlorination step is critical for the proper destruction of bacteria and virused whether you choose to automate the process with a chlorinator or add the chlorine via a manual process.

Although the absolute minimum requrements to maintain your pool can be achived with only a pump and a filter, the addition of an above ground swimming pool heater and an electronic chlorinator will extend and better maintain a healthy and happy pool environment.