Choosing the right pool filter is integral to maintaining a clean, healthy pool. The filter system you choose directly affects your pool’s cleanliness, efficiency, and ease of your pool maintenance routine.

With numerous filter options, deciding which will best meet your needs can be challenging. This guide will help you understand the pool filters available, the pros and cons of each, and the factors to consider when selecting a pool filter. Whether you’re a first-time pool owner or looking to upgrade your current filter system, this guide will provide the necessary information to make an informed decision.

Types of Pool Filters

There are three main types of pool filters: sand filters, cartridge filters, and diatomaceous earth (D.E.) filters. Each has advantages and disadvantages, so looking at your specific needs and preferences is essential before deciding.

Sand Filters

Sand filters are the most popular type of pool filter. They use a bed of sand to trap dirt and debris as water flows through. Sand filters are relatively low maintenance and can effectively keep your pool clean. However, they may struggle with finer particles and require regular backwashing to clean the sand.

The benefits of using sand filters in swimming pools comprise:

  • They are less prone to clogging.
  • Maintenance is relatively straightforward.
  • They are cost-effective.
  • The sand media remains functional for about 5-7 years before needing a replacement.
  • The efficiency can be enhanced by employing various media or additives.

Drawbacks associated with sand filters in swimming pools include:

  • High pressures can lead to reduced filter efficiency.
  • They necessitate more water for backwashing and rinsing processes.
  • They can only filter debris that is 20 microns in size or larger.
  • They demand a higher level of attention to maintain pool chemistry.

Cartridge Filters

Cartridge filters use a pleated cartridge to filter out dirt and debris. They are generally more efficient than sand filters and require less maintenance. Cartridge filters can also handle finer particles than sand filters. However, they are more expensive upfront, and the cartridges must be replaced periodically.

The benefits of using cartridge swimming pool filters are:

  • They are capable of filtering out contaminants that are 10 microns and larger.
  • They are ideally suited for pumps operating at varying speeds.
  • There is no backwashing necessary, which results in a significant reduction in water wastage.
  • They perform effectively even at slower speeds.

However, there are also some drawbacks to using cartridge swimming pool filters:

  • They demand more effort to maintain than other types of filters.
  • They require an in-depth cleaning at least once or twice a year.
  • On average, their lifespan ranges from 2-3 years.

Diatomaceous Earth Filters

DE filters are the most efficient type of pool filter, capable of trapping even the finest particles. They use a powder made from fossilized diatoms as the filter media. D.E. filters require the most maintenance of the three types, as they must be backwashed and recharged with new D.E. powder periodically. They are also the most expensive type of pool filter.

Benefits of Diatomaceous Earth (D.E.) Swimming Pool Filters:

  • E. powder can be conveniently introduced through the pool’s skimmer.
  • Capable of filtering out contaminants that are 5 microns in size or larger.
  • The cleaning process does not necessitate the use of harsh chemicals.

Drawbacks of Diatomaceous Earth (D.E.) Swimming Pool Filters:

  • Locating appropriate D.E. filters for above-ground pools can pose a challenge.
  • The filter grid requires replacement approximately every 2 to 3 years.
  • The overall costs associated with D.E. filters are high.
  • Breathing in D.E. powder may pose health risks.
  • These filters demand a thorough cleaning process annually.
  • Backwashing, an essential aspect of D.E. filter maintenance, is prohibited in some regions.

Factors to Consider When Choosing a Pool Filter

When selecting a pool filter, there are several factors to consider. Here are some things to keep in mind before making a purchase.

Pool Size

The size of your pool is crucial in determining the type of filter you need. The larger the pool, the larger the filter you’ll need to keep the water clean. A filter that’s too small for your pool will not be able to handle the volume of water, resulting in poor filtration and cloudy water. Refer to the manufacturer’s guidelines to determine the appropriate filter size for your pool.

Identify your pool’s dimensions and water volume to pick the right filter pump size and flow rate.

Let’s say your pool is 20 ft long, 10 ft wide, and 5 ft deep. Calculate its volume:

Volume = 20 ft × 10 ft × 5 ft = 1000 cubic feet

Convert this to gallons (since 1 cubic foot is about 7.48 gallons):

Water Volume = 1000 ft³ × 7.48 gallons/ft³ = 7,480 gallons

The rule of thumb is to circulate the pool’s water at least once every 8 hours:

Flow Rate = 7,480 gallons / 8 hours = 935 gallons per hour

So, you’d need a pump with a flow rate of roughly 935 gallons per hour for effective filtration.

Maintenance Requirements

Maintenance requirements vary depending on the type of filter you choose. Sand filters are the easiest to maintain, requiring backwashing every few weeks. Cartridge filters need to be cleaned every few months, while D.E. filters require the most maintenance, needing to be backwashed and recharged with D.E. powder regularly.

Budget Considerations

Pool filters come at different prices, and your budget will play a decisive role in determining the type of filter you can afford. Sand filters are the most affordable, while D.E. filters are the most expensive. Cartridge filters fall somewhere in between. Remember that the filter’s initial cost is just one part of the budget. Consider ongoing maintenance costs, such as replacement cartridges or D.E. powder.

Energy Efficiency

An energy-efficient pool filter can save you money on your electricity bill in the long run. Look for filters with a high energy efficiency rating, which will consume less power while still providing effective filtration. Variable speed pumps are also an excellent option for energy efficiency, as they can adjust the flow rate to match the filtration needs of your pool.

Pump Power and Turnover Rate

Ascertain the necessary pump power and turnover time based on your pool’s dimensions and desired water turnover.

Suppose your pool measures 30 ft in length, 15 ft in width, and 6 ft in depth.

First, calculate its volume:

Volume = 30 ft × 15 ft × 6 ft = 2,700 cubic feet

Then, convert this to gallons:

Water Volume = 2,700 ft³ × 7.48 gallons/ft³ = 20,136 gallons

Typically, pools should have an 8-hour turnover rate:

Turnover Rate = 8 hours

This informs the flow rate:

Flow Rate = 20,136 gallons / 8 hours ≈ 2,517 gallons per hour

Given the required flow rate, a 1 H.P. pump, which can typically handle 2,500 to 3,000 gallons per hour, should suffice for your pool.

Remember, these are general guidelines. Consult a pool professional or the manufacturer’s specifications for your specific setup.

Finding the best pool filter isn’t a one-size-fits-all kind of thing. Your pool has its own personality, with its own size, style, and usage habits. So, when it comes to picking the perfect pool filter, it’s all about understanding what your pool needs and how much effort you’re willing to put into maintenance. It could be a simple, affordable sand filter, a more detailed cartridge filter, or even a high-maintenance yet effective Diatomaceous Earth (DE) filter. The best choice will fit your unique pool needs and maintenance style.

Pool Types and Their Filter Needs

When choosing a pool filter, it’s essential to consider the type of pool you have. Different types of pools require different filter types and sizes. Here are some things to keep in mind:

Above-Ground Pools

Above-ground pools are generally smaller than in-ground pools and don’t require as much filtration. A filter with a flow rate of 30 to 50 gallons per minute (GPM) is usually sufficient for most above-ground pools.

Sand filters are popular for above-ground pools because they are affordable and easy to maintain. Cartridge filters are also a good option, especially if you want a filter that can capture smaller particles.

In-Ground Pools

In-ground pools are larger than above-ground pools, and they require more filtration. A flow rate of 50 to 100 GPM filter is usually sufficient for most in-ground pools.

Diatomaceous earth (D.E.) filters are popular for in-ground pools because they can capture particles as small as 3 microns. However, they require more maintenance than other types of filters. Sand filters are also suitable for in-ground pools, especially if you want a low-maintenance filter.

When selecting a filter for your in-ground pool, it’s essential to consider the size and the amount of use it gets. If you use a large pool frequently, you may need a larger filter or filter with a higher flow rate.

Remember, the type of filter you choose will depend on your pool type and size. Be sure to choose an appropriate filter for your pool to ensure that it stays clean and clear all season long.

Troubleshooting a Pool Filter

Maintaining your pool filter in optimum condition is vital, given its crucial role in preserving pool cleanliness. Filters commonly encounter specific issues. Identifying these problems can facilitate effective troubleshooting and subsequent repairs.


Notice water dripping around the filter or a puddle forming beneath it? Your pool filter might have developed a leak.

While a filter leak doesn’t significantly deplete your pool’s water, locating and fixing it before it escalates is vital.

Initially, attempt to detect the leak’s source. Examine the filter’s tank for holes. If found, patch it, but be ready to substitute the tank, as patches only last briefly.

For split-tank filters, inspect the belly for leaks. Remove the band and check the O-ring for wear or debris. If worn, it must be replaced. Use pool gasket lubricant for a better seal and to extend the ring’s lifespan.

Cycle Issues

If your filter operates in short cycles frequently, irrespective of pool usage, the filter might have a flow rate issue.

Usually, the flow rate might be excessive, indicating an overly potent pool pump or an undersized filter. If the filter size is appropriate, extend the backwash duration. Continue backwashing until the sight glass water clears, which could take a few minutes.

Short filter cycles might also result from clogs from algae or debris. Thoroughly clean the pool filter and consider a replacement if it appears worn out.

Filter Material in Pool

Spotting some filter material in the pool post-backwash is normal. However, if it’s observed otherwise, there might be an issue.

Initially, check the bolts securing the filter. Loose bolts might let particles escape into the pool. If the bolts are tight, seek other causes.

A broken filter lateral or standpipe for sand filters might be the culprit, requiring replacement.

In the case of a D.E. filter, a tear in the grid fabric or a cracked grid manifold might be the problem, needing a manifold replacement.

Water Pressure Complications

Regularly checking the pressure gauge is a vital part of pool maintenance. Water pressure discrepancies can hamper your pool filter’s effectiveness.

Low pressure could indicate a pre-filter blockage, while high pressure might signify post-filter obstruction.

Inspect the filter system thoroughly for clogs and clean it if needed. If no clogs are found, and the filter is clean, ensure the return valve is fully open, then recheck the lines for potential blockages.

In sum, picking the right pool filter depends on many things. This includes the kind of filter (sand, cartridge, or diatomaceous earth), size of your pool, how much you’re willing to spend, and how much work you want to put into maintenance. Your pool type, either above-ground or in-ground, will also affect your choice. Lastly, keeping your filter in good shape and fixing any issues quickly will help keep your pool clean all season long.

Categorized in: