Pool Filter Balls vs Sand

Pool filter balls vs sand is first a compatibility question, not a performance contest. The four sand filter makers covered here all specify #20 silica sand, and one of them says to use nothing else. Filter balls are a lightweight alternative that only some makers list for their filters. If your filter’s manual lists filter balls, as Bestway’s sand filter manual does, you can choose either and weigh the trade-offs below. If the manual specifies #20 silica sand and no other media, as Hayward’s and Pentair’s do, stick with sand or ask the maker before you switch. This article covers what each maker says, how cleaning and lifespan differ, and what the sources do and do not claim about filtration.

Safety note: a sand filter is a pressure vessel connected to an electric pump. Turn the pump off and release pressure before opening the filter or changing media, and follow the owner’s manual for your exact filter. Electrical problems belong with a licensed electrician.

Pool filter balls vs sand at a glance

Every row in this table comes from the manufacturer manuals and pages linked in the sections below. Where a figure applies only to one maker’s product, the section names that maker.

Factor	#20 silica sand	Filter balls
Makers that list it	Hayward, Pentair, Intex, Bestway	Bestway (Polysphere), for its own sand filters
Amount	Tens to hundreds of pounds, by filter size	A fraction of a pound to about 2 lb on Bestway pumps
Cleaning	Backwash and rinse with the filter valve	Bestway says not to use the backwash function; washed and reused
Lifespan	Years (maker figures vary)	Bestway says 4 to 6 months with proper care
Filtration claims	The media the filters are designed and rated around	Bestway says just as effective as sand; no independent comparison in the sources reviewed
Rule of thumb	Use the exact grade the filter’s manual names	Use only where the filter’s manual lists them

Start with your filter’s manual

The media decision belongs to the filter, not to the bag on the store shelf. Here is what four makers that sell sand filters in the US say.

Hayward: #20 silica sand

Hayward’s ProSeries high-rate sand filter owner’s manual tells owners to pour in the correct amount and grade of filter sand as specified in its specifications table, and adds that filter sand is not all the same. That table lists one media type for every model: filter sand of 0.45 to 0.55 mm, which it notes is also known as No. 20 silica pool sand, with capacities from 50 lb on the smallest tank to 700 lb on the largest. The manual does not list filter balls, glass, or any other media.

Pentair: No. 20 silica sand, with a uniformity spec

Pentair’s Sand Dollar and Cristal-Flo II pump and sand filter guide is direct: install the precise amount of filter sand listed on the filter nameplate, and use only No. 20 standard silica sand with a uniformity coefficient of 1.75 or less, which has a particle size of 0.018 to 0.022 inch (0.45 to 0.55 mm). The guide does not list filter balls or other media.

Intex: silica sand or glass media

Intex’s Krystal Clear 2,100 GPH sand filter pump page lists two media capacities: 50 lb of #20 silica sand or 35 lb of glass media. That product page does not list filter balls. If you own an Intex sand filter pump and want to use filter balls, ask Intex before you do.

Bestway: sand or Polysphere filter balls

Bestway is the maker in this group that lists filter balls for its own sand filters. The owner’s manual for its #58496E sand filter, distributed in North America by Bestway (USA), tells owners to load pool-grade filter sand or Flowclear Polysphere, and says to use 28 g (0.06 lb) of Polysphere to replace 1 kg (2.20 lb) of sand. The same manual specifies #20 silica sand of 0.45 to 0.85 mm and warns that sand of the wrong size reduces filtering performance and may damage the filter. Bestway’s sand filter pump guide says its pumps take either #20 silica sand or Polysphere filtration balls at the correct weight for the pump size.

The pattern is plain. Only one of these four makers lists filter balls, and only for its own filters; the other three sources linked here do not list them. A bag of filter balls that says it fits “most sand filters” is a claim by the ball seller, not by the maker of your filter.

Cleaning: backwash vs wash and reuse

This is the biggest day-to-day difference, and it is easy to get wrong.

Sand is cleaned by backwashing

With sand, you reverse the flow through the bed to flush trapped dirt out the waste line. Hayward’s manual says to backwash when the gauge reads 8 to 10 psi above the clean starting pressure, until the sight glass runs clear, then rinse. Pentair’s sand filter guide warns not to backwash on a timed basis such as every three days, because backwashing too often actually causes poor filtration. On a small Bestway above ground unit, the sand pump guide says to clean the sand once the gauge is over 6.5 psi, roughly once a month, and not to overclean it.

Filter balls are not backwashed on Bestway filters

Bestway’s sand filter pump guide describes the backwash setting as the function that cleans the sand and adds, in plain words, “Do not use this function with Polysphere Filtration Balls.” The same guide says the balls can be washed and reused repeatedly. Follow the cleaning directions packed with the balls for how to wash them. That changes the routine: instead of turning a valve and watching the sight glass, you open the tank and handle the media.

If you are used to backwashing sand, build a new habit before switching. Running a backwash out of habit on a filter loaded with Polysphere goes against the maker’s instructions quoted above.

Weight and handling

Weight is where filter balls have a clear, documented edge. Bestway’s sand pump guide says its pumps need between 20 and 80 pounds of sand depending on size, while Polysphere balls need between 0.5 and 2.2 pounds. Inground filters take far more sand: Hayward’s ProSeries chart runs up to 700 lb on its largest tank.

Sand also takes care going in. Pentair’s guide says to check the lower underdrain for broken or loose laterals first, fill the tank about half full of water, and pour the sand in slowly so its weight does not damage the laterals. On a small above ground filter pump, a sand change is a manageable afternoon. For an owner who cannot lift heavy bags, or a filter tucked into a tight corner, a light media can matter.

How long each one lasts

Sand lasts years; filter balls last months, by the makers’ own figures.

• Sand: Intex’s 2,100 GPH sand pump page lists replacement of sand every 5 years. Bestway’s sand pump guide says its sand can last up to three years with proper care.
• Filter balls: the same Bestway guide says Polyspheres last 4 to 6 months with proper care.

Why sand wears out at all: Pentair’s Sta-Rite training manual explains that dirt is trapped in the tiny openings, cracks, and crevices between sand grains, and that over time the grains become round and smooth and filter less effectively. That can take as little as a year or many years, depending on how fast water moves through the bed. On a seasonal pool, one bag of balls may cover a summer, while sand may cover several summers. Count the replacements you would buy over the years you plan to keep the filter, not just the first fill.

Filtration: what the sources say and do not say

Bestway’s filter pump guide describes its Polysphere balls as small, cotton-ball-like spheres that are “just as effective” as sand. That is the maker’s claim about its own product in its own filters. None of the sources linked in this article publishes an independent side-by-side measurement of particle removal for filter balls vs sand, and the other three makers’ sources linked above do not rate filter balls at all. We have no basis to say one media gives clearer water than the other.

What the sources do agree on is that grade matters for sand. Hayward and Pentair specify a narrow particle size, Pentair adds a uniformity limit, and Bestway warns that the wrong sand size reduces filtering performance. If you stay with sand, buy the grade your manual names rather than any sand labeled for pools.

What about glass media?

Glass is a third option some owners consider. Intex’s sand pump page lists a glass media capacity (35 lb against 50 lb of sand), so glass is a listed option there. Hayward’s ProSeries manual lists only filter sand in its specifications table, so glass is not a listed option for those filters. The rule is the same as for filter balls. Use what your filter’s maker lists.

Who should choose sand, and who should skip it

• Choose sand if: your filter’s manual names #20 silica sand only, you want media that lasts years, or you like the turn-a-valve backwash routine.
• Skip sand if: lifting heavy bags of sand is not realistic for you and your filter’s maker lists a lighter media, or you have no place to send backwash water and your filter supports a media that is not backwashed.

Who should choose filter balls, and who should skip them

• Choose filter balls if: you own a filter whose maker lists them, such as the Bestway sand filter covered above, and you want light media you can wash and reuse.
• Skip filter balls if: your manual calls for sand only, you do not want to replace media every few months, or you would rather keep the backwash routine your filter was designed around.

For more on filters, pumps, and media, browse our pool pumps and filters section. If you are staying with sand, the next step is picking the right pool filter sand for your filter’s grade.

When to call a pool professional

Changing media on a small above ground filter is usually an owner job if the manual walks you through it. Call a pool professional if you find cracked or broken laterals when the old media comes out, if the tank, clamp, or valve shows damage, or if pressure stays high after cleaning. Hayward’s manual warns never to operate the system above 50 psi, and Pentair’s guide says the filter is a pressure vessel that should never be serviced under pressure. If the pump’s GFCI trips or the pump will not start after you put the filter back together, call a licensed electrician rather than resetting it over and over.

FAQ

Can I put filter balls in any sand filter?

No. Check the filter’s manual first. Bestway’s sand filter manual lists Polysphere balls for its filter, while the Hayward and Pentair manuals specify #20 silica sand and list no other media.

Do filter balls need backwashing?

Not on Bestway filters. Its sand filter pump guide says not to use the backwash function with Polysphere balls, and that the balls are washed and reused instead.

How many filter balls replace the sand?

For Bestway filters, the #58496E manual says 28 g (0.06 lb) of Polysphere replaces 1 kg (2.20 lb) of sand. That ratio is Bestway’s figure for its filters; do not apply it to a filter whose maker does not list filter balls.

Can I mix filter balls and sand?

None of the manuals reviewed for this article describes mixing them. Bestway’s manual presents Polysphere as a replacement for sand, so load one media or the other, not both.

Are filter balls better than sand?

They are lighter and are not backwashed, but they need replacing far sooner: Bestway gives 4 to 6 months for its balls and up to three years for its sand. Bestway says its balls are as effective as sand; no independent comparison was found in the sources reviewed. For filters that call for sand only, sand is the right choice.

About the author