Pool Filters, Which Type Should I Use?  

by Pool Builders on 09-14-2010 in Articles

This question often pops up from potential swimming pool owners, which type of filter should I use? The question it's self is quite broad and is dependant on reliability and maintenance.

Sand Filters
Sand filters are a great as they are cost effective to maintain but are not the best. A sand filter works by having the dirty water pushed through the top and then the clean water exits from the bottom. Overtime the sand will become clogged with particles from the pool and the water pressure on the filter will increase. To keep a sand filter clean it must be back-washed every few weeks. Usually the pool with have a backwash valve which would allow the sand to be flushed while still in situ. If the sand ever got extremely dirty it would be fairly easy and inexpensive to replace.

The filtering properties of sand are the least effective, smaller particles may pass through the filter and back into the pool.

Cartridge Filters
Cartridge filters are regarded as economic and low maintenance. These type of filters are more efficient than sand filters as the filter has much more available area to filter than sand. These filters do not clog up as often as sand filters meaning that you do not have to get your hands dirty as often.

Usually Cartridge filters come in two variety's there are those that contain inexpensive filter elements and therefore do not last as long, or there are the the ones which contain expensive elements and tend to last 5 years or more.

However both types of cartridge filters are designed to run at a lower pressure than sand filters which means there is less back pressure on the pump meaning that you get greater water flow.

These types of filters generally need to be hosed off once or twice a season in comparison to a sand filter which must be back flushed every few weeks. From a maintenance point of view this is an advantage as it means the cartridge filter requires less maintenance than the sand counterpart.

Cartridge filters are more efficient in terms of particle filtration than sand filters but are not as good as diatomaceous earth filters (which we shall look at next)

Diatomaceous Earth Filters
Diatomaceous earth is a naturally occurring sedimentary rock which easily crumbles into whiteish fine powder. The composition of diatomaceous earth consists of fossilized remains of diatoms which are a type of hard-shelled algae.

Diatomaceous earth is used to coat a grid within the filter housing, as the water passes the diatomaceous earth the dirt is left behind. The water is then passed through a fabric element and out of the filter.

These types of pool filters are the most efficient and can filter particles down to approx 5 microns. Diatomaceous earth filters do need to be backwashed as do sand filters but you must top up the filter occasionally with more diatomaceous earth powder.

Diatomacous earth filters do run at a higher pressure than cartridge filters therefore you can expect some loss of flow.

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