Are you looking for the right pool filter to keep your swimming pool sparkling clean? With so many different types of pool filters available, choosing the right one can be overwhelming to say the least. But don’t stress; this handy pool filter buying guide will help you decide which swimming pool filter is the right one for you. After all, a good pool filter is an essential part of a clean, healthy pool.

Choose a Filter to Match Your Pool Type and Size

The pool filter and pool pump go hand in hand to act as the filtration system in your pool, circulating and cleaning the water to keep it free of harmful bacteria and dirt. When purchasing a pool filter, make sure that the filter you choose is sized properly for your pool pump and your swimming pool. A pool pump for a large pool with a higher flow rate pumps more gallons per minute (gpm) and will function properly with a larger pool filter. Smaller pool pumps for smaller pools should be paired with smaller pool filters. A popular option for many above ground pools is to purchase a combination pump and filter that includes all of the pipes and fittings needed for installation.

Types of Pool Filters

Let’s take a look at the three most popular types of pool filters that will help you open, maintain, and clean your pool.

Cartridge Pool Filters

The cartridge pool filter is gaining popularity when it comes to spas and small above ground pools, and has been a popular choice for inground pool owners as well. This particular cartridge is both easy to maintain and clean throughout pool season. A cartridge filtration system works by pushing water through the filter membranes, trapping particles in the cartridge fibers, and sending clean water back out to the pool.

When the pressure gauge reads ten points above the normal reading, it is time to remove the filter and spray it with a garden hose to get rid of excess dirt. Over time the cartridge will eventually lose its filtering ability, which means that a replacement must be installed to keep the filter running smoothly. Typically, cartridges need to be replaced every 3-5 years, depending on how often you filter your pool.

Here are some helpful hints for using a cartridge pool filter:

  1. No ‘Backwashing’ - With this type of filter, you do not need to backwash to maintain it. Although this filter requires more manual labor than most, it might prove worth it in the long run. Backwashing sand and DE filters wastes water, so this is the most energy efficient choice overall.
  2. Use Clarifiers - You utilize clarifiers and sanitizers in your pool water, so why not your cartridge filters? Consider one of our clarifiers for a sparkling clean filter in no time.
  3. Remove Debris Regularly - In order to make your cartridge filter last with as few replacements over time as possible, you need to continuously check your pool water for additional debris, dirt, and organic remnants that could clog the filter chamber. Circulate and balance the chemicals in the water frequently to be sure bacteria and algae don’t grow and contaminate your pool water, clogging the filter and creating extra work for you.
  4. Run Your Filter - A good rule of thumb is to run your pool filter one hour for every 10 degrees of air temperature. So, if the temperature is in the 90s, run your filter for 9 hours per day. This will keep your pool water clean and free of contaminants and algae. If you experience cloudy water or an algae bloom, you should run your filter continuously until the problem is resolved.

DE (Diatomaceous Earth) Pool Filters

The DE pool filter is by far the most efficient filter in its category. Next to nothing will get past the filter chamber, even the smallest particles that are invisible to the naked eye, as small as 2 microns! DE filters work by using a filter media called diatomaceous earth. This is a porous powder that allows water to pass through it, but not much else, so that you can achieve unmatched water clarity. DE powder is relatively inexpensive, though DE filters tend to be more expensive than Cartridge and Sand filters. When you need to add more DE to your filter system, simply sprinkle it into the skimmer where it will be sucked into the filter tank.

Helpful tips for using a DE pool filter:

  1. Backwashing - When your water pressure gauge reads 8-10 lb above the clean reading, it is time to backwash your filter. All you need to do is turn a valve to allow your pool water to filter backwards to rid it of dirt, debris, and bacteria. Depending on the style of your DE filter; you might have a push valve (aka slide valve) or a multiport valve to complete this task.
  2. Cleaning the Grid - The DE filter grid is where the dirt and contaminants are trapped inside of the filter tank. These grids need to be cleaned at least a few times a year to remove buildup. Remove the grids and rinse them with a garden hose, then soak them overnight in a filter cleaner.
  3. Replacing the Grid - DE filter grids can last up to 10 years. Over time, however, they may rip or the plastic may break down, and they will need to be replaced. It is a good idea to keep a set of replacements on hand just in case.
  4. Remove Debris from the Pool - Just like with a cartridge filter, you need to regularly clean the pool and check your skimmers and filter baskets for additional debris, dirt, and organic remnants that could clog the filter chamber. Circulate and balance the chemicals in the water frequently to prevent algae and bacteria growth.
  5. Run Your Filter - Run your pool filter every day when your pool is open, for about 8-12 hours per day. Or follow the 1 hour for every 10 degrees of air temperature rule.

Sand Filters

Sand filters are the least expensive pool filter option, and they are also very low maintenance. Sand filters tend to trap particles within the 20-100 micron range. They work by passing water through a sand bed within the filter tank that traps the fine particles in the water.

  1. Backwashing - Just like the DE filter, the sand filter also requires ‘backwashing.’ If you notice the pressure gauge is between 8-10 lb above the clean reading, then you need to backwash to remove all debris from the filter.
  2. Cleaning the Sand Bed - Use sand filter cleaner to clean and disinfect your sand bed.
  3. Replacing the Sand Bed - A well-maintained sand filter will last for many years. The sand itself can last up to 7 years before it needs to be replaced. To remove the old sand, follow the manufacturer’s instructions to disconnect the hoses and empty the sand. You cannot add just any new sand to this filter, you need to use pool filter sand (#20 silica sand 45-55mm). After you pour the new sand in, be sure that it is centered properly so no excess sand escapes into the pool water.
  4. Run the Filter - Run your filter for 8-12 hours per day or for 1 hour per ten degrees of outside air temperature.

Now that you understand the basics of what to consider when purchasing a pool filter, you can choose the one that will fit your pool and your lifestyle. The right filter will keep your water sparkling clean and reduce your time spent on pool maintenance.

Doheny’s carries a huge selection of quality pool filters from top brands like Hayward and Pentair, as well as our own Doheny’s brand. If you have questions about any of our pool filters or other pool products, call us at 800-574-7665 or visit us online at