Filters can be above-ground or in-ground pool models, or both. Some models are also multipurpose pool/spa/aquarium filters. Popular brands include Intex, Hayward,Pentair (Triton, Purex), Sta-Rite (now merged with Pentair), Waterway, Jandy, Pac-Fab (Nautilus), Waterco, and Doughboy. Prices range from under $ 50 to a few hundred dollars; depending on the type, size and brand.
How to Choose the Right Swimming Pool Filter
All filters should have a flow-rate (GPH, gallons per hour) rating. The larger the filter, the higher the flow-rate it can handle. The filter's flow-rate should be the
same or higher than the pump's flow-rate. A larger flow-rate filter has less resistance, putting less strain on the pump.
Filters are sometimes specified according to pool size. For example, a filter can be specified for a maximum pool size of 19,000 gallons and assuming an 8 hour
turnover time. This means that the filter can handle 19,000 gallons in 8 hours, or 19,000 / 8 = 2,375 GPH.
There are three main types of Swimming Pool Filter
: cartridge, sand, and diatomaceous earth. When choosing a filter, filtration performance and initial cost are important considerations.
Maintenance effort and cost are also important. These are more difficult to know beforehand as they depend on how dirty the pool water is (pollen count, number of
people, sun tan lotion used, amount of algae-promoting sunlight, etc), and the size of the filter relative to the size of the pool. The filter-change numbers given
below are based on manufacturers' recommendations and user reviews, and will vary depending on actual conditions.
The filter should be washed or replaced, when the filter begins to be blocked by trapped dirt. This is determined by comparing either water flow-rate or filter water
pressure, against the numbers when the filter was new. Details will be in the manufacturer's owner's manual.
The filter should have a built-in pressure gauge. Cheaper cartridge filters do not have a pressure gauge. It's therefore necessary to eye-ball the cartridge condition,
water flow-rate, or pool clarity.
Cartridge Swimming Pool Filter
These are the cheapest type of filter and are often supplied together with above-ground pools.
Advantages
Low initial cost.
Easy to install and set up.
Easy to maintain, just clean or replace the cartridge, but with daily or weekly effort.
Medium filtration performance (size of dirt particles trapped).
Disadvantages
Frequent filter washings (every day or week) and replacement (every few weeks or months) required. Shops might not sell filters all year round (online sales websites
are one solution), and the cost of replacement filters adds up.
Filter needs to be manually hosed down for cleaning. There is no backwash setting. Special filter cleaning solutions are available for more thorough cleaning.
Slow Sand Filters
This traditional design of filter typically has a bed 1 to 2 metres deep, and can be rectangular or cylindrical in cross section; it is used primarily to treat surface
water. Slow sand filters have a number of unique qualities:
Use biological processes and are non-pressurized systems.
Do not require chemicals or electricity to operate.
Cleaning is traditionally by mechanical scraper; however, some operators use "wet harrowing", where the sand is scraped while still under water, and the water used for
cleaning is drained to waste.
Maximum required throughput of water is achievable with one or more beds out of service.
Require relatively low feed turbidity levels.
Produce water at a slow, constant flow rate and are usually used in conjunction with a storage tank for peak usage.
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