Swimming pools have traditionally had either a sand, cartridge or DE filter to clean the water. Let's look at the differences of each type of filter.

SAND FILTERS, the first type of filter operates using fine filter sand inside the tank or vessel to gather the dirt and debris from the pool. The pool water is sent to the filter from the pool pump to the top of the tank and a fitting inside the vessel called the distributor "rains" the water down and through the sand. As the water migrates down through the bed of sand the pool water is collected by the laterals inside the bottom of tank and returned to the pool filtered and clean. The sand inside the filter can last for many years if the filter is "backwashed". What is backwashing? Backwashing is when the water flow inside the filter is reversed (using the selector valve outside the filter) and the dirty water and debris are flushed out through the waste line of the pool system. During backwashing, some sand will be lost each time and the water level of the pool will be lowered. When it is time to replace the sand, the old sand will need to be removed, either by hand or tool and the filter will need to be replenished with new fresh filter media.

The second type of filter is a CARTRIDGE FILTER, it uses a replaceable cartridge element to capture dirt and debris from a pool and or spa. The cartridge is housed in a tank, the upper dome or lid is held on by a knob or clamp and is manufactured with remove ability in mind. When the cartridge has collected enough dirt and debris the cartridge is removed, hosed off, dirt removed and the element is replaced back into the tank. The cartridge will last for many years if it is cleaned on a regular basis and not allowed to become over filled. Cartridge filters when cleaned do not require backwashing; the pool water level is unaffected during cleaning. Cartridge filters are a perfect choice for spas due to this fact and the fact of easy of cleaning.

The DE FILTER is the third type of filter we will discuss. This type of filter has grids which are inside the tank and which hold a thin layer of DE. As the pool water is sent to the tank from the pool pump it passes through these grids, covered with DE and the DE captures the dirt and debris for removal. The diatomaceous earth filter can be "backwashed" periodically to remove dirt and debris from inside the filter. Just like the sand filter each time the filter is backwashed, the pool level is lowered and some DE is lost. Eventually the filter will need to be disassembled, the old DE removed and fresh diatomaceous earth replaced inside the filter. Fresh DE can be added directly to the filter tank while the tank is open for servicing.

After looking at all three types, which type is the best? All three types offer excellent filtering capabilities and if maintained in top working order, all three can and will keep your swimming pool and or spa clear and crystal blue. The filter is a key part of your pool system, if it does not function correctly expect to spend extra time and effort maintaining your backyard investment, maintain it on a regular basis and enjoy your backyard paradise each and every day.