Pool Pumps & Filters

Swimming Pool Pumps

The term “pool pump” is used to describe the entire pump unit, which consists of the electric motor, an “impeller” and “diffuser” (which actually move the pool water), and the strainer basket and housing that this basket fits down into. A swimming pool pump uses centrifugal force to push pool water, and relies mostly on atmospheric pressure to move water from the swimming pool down the plumbing to the pool pump. Above ground swimming pool pumps are “gravity fed”, and must be installed below the water line of the above ground swimming pool. Because the pool pump is situated below the level of the pool water, atmospheric pressure pushes water down the pipe from the pool to the swimming pump at ground level.  The above ground pool pump can then push the pool water through the pool filter and plumbing back to the swimming pool.

Most inground swimming pool pumps are installed above the level of the water inside the swimming pool, up on the decking, or inside an equipment shed near the pool. Before an inground pool pump can be turned on, the plumbing leading from the swimming pool to the pump must be filled with water. This is called "priming" the pool pump. As mentioned above, swimming pool pumps create very little suction to draw water from the pool, up to the pump. Once the pipe from the pool up to the inground pool pump is filled with water, the pool pump can then push the water through the pool filter and plumbing back to the swimming pool. Click here to shop for quality pool pumps and pool filters at competitive prices.

Pool Pump Sizing

Swimming pool pumps are available in a wide range of sizes, and are measured in horsepower (listed as HP on the label of your pump motor). If you are replacing your pool pump, and you will continue to use your old pool filter, your new swimming pool pump needs to be the same size (horsepower) as your old pool pump. If you replace your old pool pump with a different size pump, this new pump may not be the correct size for your old pool filter. This may cause water problems or damage the pool filter. If you will be replacing both your pool pump and your pool filter, please see the Pool Filter Sizing information below.

Swimming Pool Filters

There are three basic types of swimming pool filters on the market today. These three different pool filters are called sand pool filters, cartridge or "element" pool filters & DE pool filters. Each type of pool filter is built to remove fine dirt and debris from pool water, but each performs this function in a different way.

Pool sand filters consist of a tank filled with sand with a valve on top, and plumbing with slits or slotted holes in the bottom of the tank underneath the sand. Dirty water from the pool is piped to the valve on top of the filter, which spreads the water out across the surface of the sand inside the filter tank. As the water travels down through the sand, all of the dirt in the pool water is left behind trapped in the sand. The clean water at the bottom of the tank is collected by the slotted plumbing, and is piped up the middle of the sand bed and back out the valve on top of the filter to return back to the pool.

Sand filters do not have the best filtering capability, but they are the least expensive type of pool filter and require very little maintenance. Sand pool filters will trap particles of debris as small as 12 "microns" in size, which is adequate for any outdoor swimming pool. The only regular maintenance required for a sand pool filter is a quick cleaning once every week or two. This quick and easy cleaning process is called "backwashing", and basically means reversing the flow of water through the sand filter tank. Instead of flowing down through the filter sand, the water flows up through the sand during backwashing and the dirt that has collected in the sand is carried out of the filter. In addition to backwashing the sand inside the filter tank should be changed out with fresh sand every 2-3 years.

Cartridge or "element" pool filters consist of a large tank, with a pleated paper or polyester element inside that takes up nearly the whole interior of the tank from the bottom to the top. Dirty water from the swimming pool enters the tank around the outside of this filter element and the water is drawn through the element. The dirt and debris is left behind on the outside of the element, and the clean water is collected in the center of the element and piped back to the swimming pool. Cartridge pool filters require periodic cleaning to remove the loose debris from the filter element, and once or twice each swimming season the filter element will need to be soaked in a filter cleaning solution to remove more stubborn stuck-on debris and oils. A cartridge filter is cleaned by removing the top of the pool filter tank, and the filter element is lifted out of the tank. The filter element is sprayed down with a garden hose to rinse off all of the loose debris that has been collected. Depending on how a cartridge filter is sized and how dirty the swimming pool is, the element may need to be cleaned once a month, once a week or more frequently. The filter element may last only one year, or may last many years depending on use and how carefully it is cleaned. Cartridge pool filters will trap particles of debris as small as 8-10 microns in size.

DE pool filters are similar to cartridge filters in construction, except a fine powder called Diatomaceous Earth coats the filter element inside the filter tank of a DE pool filter. This Diatomaceous Earth powder (commonly referred to as DE) is ground coral, or a synthetic alternative with the same consistency as real DE powder. The filter element inside the DE filter does not actually trap the debris by itself. The coating of DE powder on the outside of the element is actually used to collect the fine debris as the dirty pool water is passing through. A DE pool filter traps debris down to 2-3 microns in size, resulting in better water clarity than pool sand filters and cartridge pool filters can provide.

When a DE filter is full of dirt from the pool water and the pressure gauge indicates that it needs to be cleaned, you do not have to immediately backwash the filter, like you would with a sand filter. You can first regenerate or “bump” a DE filter to clean it. This regenerating process shakes or scrapes all of the DE powder and debris off of the filter element inside the pool filter tank. All of the debris and DE powder settles to the bottom of the filter tank, and when the filter is turned back on the DE powder recoats the filter element to continue to filter the pool water. This can be done several times before all of the debris and DE powder must be backwashed out of the tank. The backwashing process for a DE pool filter is similar to the backwashing of a sand pool filter. The flow of water through the filter is reversed, and all the dirt flows out of the filter through a waste port.

A disadvantage of the DE filter is that each time you backwash the dirt out of the pool filter tank, the DE powder also flows out. Before you can continue to filter, you need to add fresh DE powder. This means there is the ongoing cost of fresh DE powder for the pool filter, for the entire life of the swimming pool. Sand filters and cartridge pool filters only require occasional replacement of the filter element. Another disadvantage of a DE pool filter is that real DE powder is considered toxic. Although DE powder is naturally occurring coral, it is harmful to people and animals. You must be very careful while adding DE powder to the system, and it is suggested that you wear eye protection and a face mask to prevent the powder from entering your body. The used up DE powder that is backwashed out of the filter cannot simply be piped out onto the lawn. Most pool owners will dig a hole in the ground near the pool filter, backwash into the hole and bury the used powder. Another method is to back wash the used DE powder into a special “separation tank” which traps the used DE powder. Several non-toxic DE powder alternatives are available to simply avoid this issue altogether, but these products typically run about twice the cost of real DE powder.

Pool Filter Sizing

The goal of your swimming pool filtration system is to turnover all of the water in your swimming pool in 8 to 12 hours. This means you will need to know approximately how many gallons of water your swimming pool holds to properly size a swimming pool filter and/or pump. Each manufacturer of swimming pool filters will provide performance data for their pool filters, telling you how many gallons of water each filter model can process in 8 or 12 hours. Most pool equipment dealers will sell pool filter and pool pump combinations, with a pump already matched to the filter. It's as simple as looking at the pool filter performance chart, and selecting the equipment package for your size pool.

If you are purchasing a new pump and filter separate from each other you should first select the correct size filter for your pool. The pool filter manufacturer's performance data will tell you the "design flow rate" of the pool filter, expressed in gallons per minute (GPM). The pool pump manufacturer's performance data will provide you the flow rate of each pump in GPM, and you can simply match the two up to find the correct size pump.