When building a new pool or replacing existing equipment, choosing a new pool filter may seem like a daunting task at first with so many options on the market. Each of the three main types of pool filters has their own benefits and drawbacks.
Sand Filters
Sand filters work by pushing the water through a large body of sand located within the filter. Sand filters are cleaned by a process known as “backwashing”, where the water flow is reversed by turning a multiport valve, and the dirt/waste particles are pushed to the top of the sand and then flushed out through a waste pipe. Silica sand, the most common media used in sand filters, can filter particles down to 20 microns. Some pros of sand filters include
-The easiest type of filter to clean – no filter disassembly is required to clean, and no loss of media occurs during backwash process.
-Filter sand can last up to 5 years before needing to be replaced.
-Recycled glass media can be used in lieu of sand, which increases filtration ability from 20 microns to 3 microns.
While the sand filter may be the easiest to maintain, they have definite drawbacks.
-Silica sand has the lowest micron filtration ability compared to Cartridge and DE filters
-Replacing the sand can be a very challenging physically, and may require the assistance of a hired professional with special equipment
-When converting from a cartridge filter, a new multiport unit, as well as a new filter, must be installed, often requiring the plumbing to be adjusted, resulting in a very high cost to convert.
-Sand filters must be back washed much more frequently than a DE filter.
-Lateral units on a sand filter can crack with age, resulting in a spilling of media back into the pool.
DE Filters
DE filters work by pushing water through a filter consisting of 7 grid units coated in a fine powder known as diatomaceous earth, or DE. DE filters, like sand filters, are cleaned through a backwash process, which flushes all material, including the DE, off of the grids and through a waste pipe. Benefits of a DE filter include
-Greatest filtration ability, down to as little as 2-3 microns
-Can go months without needing to be back washed or cleaned
-Grids can last several years if cared for properly
Some drawbacks of DE filters include
-DE filter media must be added to filter after each backwash. This can add an additional cost to pool maintenance if the pool is used heavily and regular backwashing is required.
-DE filters are typically the most expensive filter option
-The filter must be disassembled and the grids cleaned once per season. This can require the purchase of special tools, and the grids can be torn during this process if not done carefully.
-DE is a known carcinogen if inhaled.
-Like sand filters, a backwash valve and additional plumbing work is needed when converting from a cartridge filter
Cartridge Filters
Cartridge filters are the simplest type of pool filter, consisting only of a single or multiple cartridge units. Cartridge units are made of finely pleated sheets which collect debris as water is pushed through. Cartridge filters are not cleaned through backwashing like the other filters, but through disassembling the filter and manually rinsing the waste buildup off of the cartridge. Some benefits of cartridge filters include
-Easily the least expensive type of filter, and by far the easiest to install
-Excellent choice for smaller pools that do not receive regular usage
-Cartridge units easy to replace and fairly inexpensive when compared to replacing filter sand or DE grids
-Cartridge filters are typically easy to take apart and clean
Some drawbacks include
-Cartridge filter will need replacing much more often than DE grids or Filter Sand
-Disassembling the filter unit is required in order to clean the filter. This can become cumbersome for pools that receive a lot of usages and need constant cleaning or vacuuming.
-Oils can build up on the cartridge, which requires a special filter cleaning solution to remove
-When converting from a sand or DE filter, extensive re-plumbing can be required to remove the backwash and multiport lines.
-Cartridge filters do not have a built-in system to drain water from the pool like sand and DE filters. This can become a problem when needing to drain water from the pool, especially when trying to dilute for high levels of cyanuric acid.
Choosing the right filter
Overall, one must assess many factors when choosing the right filter for them, including their current equipment setup, the usage rate of their pool, their initial start-up budget, knowledge of disassembling their equipment, and their time commitment to maintaining their pool. Knowing the benefits and drawbacks of each filter will allow you to choose a filter that best suits the needs of you and your pool. Feel free to contact us for more information on this and a variety of other pool related topics!