One of the most commonly asked questions in the pool industry is which pool filter is the best - Sand, DE or Cartridge? Everyone seems to have a different opinion on which filter is the best in regards to performance and maintenance.
I've listed Pros and Cons of each pool filter type, so you have enough information to make an educated decision on which filter option is the best for your particular swimming pool.
Performance of swimming pool filters is measured in two ways - filter area and filter rate. The filter area is the total area or square feet of filter media surface of which water can flow through. Filter rate is measured in gallons per minute per square foot.
Pros - Oldest and most common type of pool filter, and certainly the easiest filter to operate. Out of all 3 filter types, a sand filter is the least expensive pool filter to purchase for your swimming pool. Cleaning of a sand filter is done by backwashing the filter, which is a very easy process.
Cons - The sand filter will filter the pool water to the largest particle size, approximately 20 microns. You have to discharge water when you backwash so this is wasting water and chemicals. I know when I built my pool I paid someone to deliver water to my pool to get started it seems foolish to me to discharge that water onto the ground. The sand inside the filter should be changed every 5-7 years - not to difficult or expensive.
Maintenance required- Sand filters are normally very reliable with very little repair costs. Some of the items that normally need to be replaced with a sand filter would be the gasket for the backwash valve, replace a cracked lateral at the bottom of the filter tank. Filter sand will need changing every 5-7 yrs.
Estimated cost of ownership over 10 years (additional repair & supply costs) - Over 10 period of time the estimated cost of ownership for repairs would be approximately $250, assuming two repairs, and two sand changes.
Pros - The DE filter has the advantage of filtering the water to the smallest particle size (2-3 microns) and will keep the water cleaner than a sand filter or cartridge filter. This can translate to less pump run time and less sanitizer needed to keep the water clean and clear. DE is the most superior form of pool filtration.
Cons - DE filters require the most amount of maintenance. After backwashing your filter you must add replacement DE powder through your skimmer to recoat the grids inside your pool filter. With a DE filter you typically have to take the filter apart every 6 months to clean the filter grids with a high pressure hose. The other disadvantage is that although natural, DE powder is hazardous to breathe and is labeled a mild carcinogen. Lastly, the DE filter is typically the most expensive filter to purchase.
Maintenance required - DE Filters need new filter grids inside pool filter about every 10 years. During the season normally have to take apart filter to clean grids or fingers inside a couple of times a season. Every time you backwash filter you must add DE back through your skimmer.
Estimated cost of ownership over 10 years (additional repair & supply costs) - The estimated repair and replacement cost for a DE filter would be approximately $500, assuming two repairs, DE powder cost and filter grid replacement.
Pros - There is no multiport valve necessary so plumbing is easier, and with no multiport valve there is no back washing, which is environmentally friendly because it conserves water and because DE powder is not discharged. And since there is no multiport valve, there are no multiport valve repairs. Cartridges filter the water better than sand, but less than DE.
Cons - With a single pleated filter inside you need to clean the filter cartridge fairly often. With the large Cluster type of filter, normally 4 filters - you still need to clean the filters but maybe only once or twice during the pool season. In order to clean the filter cartridge or cartridges you must open up the filter and take cartridges out and spray them down with a hose or use a filter cleaner to clean the cartridges.
Maintenance required - Cartridge filters are cleaned manually by spraying them down with a hose or soaking them in a filter cleaner to clean the pleats on the paper cartridge. Allow to dry fully before reinstalling into the filter. Replace filter cartridges every 12-15 cleanings.
Estimated cost of ownership over 10 years (additional repair & supply costs) - The estimated cost over a 10 year period of time would be approximately $500. assuming replacing your filters two times during ten years, plus a few other small parts.
There are advantages and disadvantages to pool filters and everyone within the pool industry has a different opinion of which filter type they prefer. Which filter to use depends on a pool owners preference - but it is very important to make sure the filter is sized accordingly and correctly to the pool size and the pump size. More important than brand, color or type - large pool filters can make pool maintenance a whole lot easier!
SPP Pool Expert