Different Techniques in Pool Filtration
Sand is the oldest method of pool filtration and is still the most widely used.
The right pool filtration system performs most of the heavy lifting to keep a pool clean and free from algae and other debris. Three major filtration types can be installed in the closed-circuit circulation of a pool pump, each with pros and cons. When searching for the right option, the primary factors are cost, filtration quality (measured in microns), maintenance, and pool size.
Sand filtration
Sand is the oldest method of pool filtration and is still the most widely used. This is due to its low cost and maintenance. The filter passes water through tightly packed sand of 45 and 55 millimeters, which filters out debris. It’s able to filter to about 50 microns of fineness.
The sand is cheap and must only be replaced every five to eight years, depending on pool size and usage. Over time, debris will clog the sand (indicated by increased entry pressure on the filter shell’s gauge), and one must backwash the system.
Sand filtration needs frequent backwashing to keep the system running smoothly. Backwashing uses much water and requires a sewer connection to drain efficiently. Both the water usage and connection can prove expensive.
Glass is a newer replacement for sand in filters and performs the same function with less bio-fouling and an even finer filtration level of five microns.
Cartridge filtration
Cartridges are smaller filters that work best with smaller pools. The cartridge is a three-tiered filtration system that passes water through a skimmer for large debris, a basket for finer particles, and a polyester filter for any remaining impurities. This is a finer filtration method than sand, and the larger surface area can achieve anywhere from 10 to 20 microns of fineness.
Compared to sand filtration, there’s no need for backwashing with a cartridge filter, saving on water and electricity usage. The cartridges are more expensive, though, and will need to be replaced biannually for optimal efficiency.
Pocket filters are similar to cartridge filters and, while offering less filtration and fineness, can be washed and reused in some instances.
Diatomaceous earth (DE) filtration
DE consists of the fossilized remains of diatoms and microalgae. Pour DE into the container, where it will attach to internal grids, providing a wide filtration surface area. Just as algae filter water, the porous nature of diatoms traps particles and enables a filtration fineness unmatched by other methods: three to five microns.
This detailed filtering comes at a price, though. Like sand filtration, one must regularly backwash DE filters and insert the new earth immediately. Moreover, the internal grids will need cleaning every few months.
Like sand filtering, one must connect them to plumbing for backwash drainage. This is more easily accomplished with the help of a professional pool service.
In Depth Pool Service is a residential pool service for El Dorado Hills and surrounding areas. We provide cleaning, maintenance, and pool equipment repairs. Call us at (916) 633-7729.
