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How many pool filter balls you actually need

Updated: 21 October 2026

You are standing over a sand filter with last season’s sand still in the tank, and a bag of fibre balls that claims to replace a whole sack. How many pool filter balls you put in depends on the kilogram figure in that pump’s manual, and on a gram table the pump maker or the ball maker printed. A title that says “replaces 50 kg” is a slogan, not the fill. The [filter balls comparison](/hub/pool-care/filter-balls) lines up seven amazon.co.uk bags from about £3.99 to about £13.99. This page is the check before you treat any slogan as a quantity. A qualifying purchase can earn a commission at no extra cost to you.

You are standing over a sand filter with last season’s sand still in the tank, and a bag of fibre balls that claims to replace a whole sack.

Our top picks

Windspeed Windspeed filter balls, 1400 g title

Best overall

Windspeed Windspeed filter balls, 1400 g title
6.0/10about £11.99
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Bomxmon Bomxmon filter balls, 1.54 lb

Best value

Bomxmon Bomxmon filter balls, 1.54 lb
7.3/10about £9.99
View offer
Intex Intex fiber balls, 500 g (29045)

Rank 3

Intex Intex fiber balls, 500 g (29045)
9.3/10about £10.99
View offer
On this page
  1. 1.Start from the sand weight in the pump manual
  2. 2.Intex grams and Bestway grams are different documents
  3. 3.What the marketplace slogans in this comparison actually say
  4. 4.Five checks before you order

Start from the sand weight in the pump manual

The sand load in the manual is the input, not the weight of balls you tip in. A tank that names sand, or sand and glass, is a candidate only when the pump maker or the ball brand says balls are an accepted fill. Intex’s support page says fibre balls are not a stand-in for a cartridge. If the manual is silent, a bullet that says “suitable for filter pumps” is not permission. Intex prints grams by SX model. Bestway prints 28 g of Polysphere per 1 kg of sand. Whether to leave sand at all is filter balls vs sand.

Intex grams and Bestway grams are different documents

If you own an Intex sand pump, use Intex’s table, not a generic “500 g equals 18 kg” line. Intex support lists SX925 at 200 g, SX1500 at 350 g, SX2100 at 650 g, SX2800 and QX2100 at 1,000 g, and SX3000, SX3200, and QX2600 at 1,500 g. One 500 g Intex 29045 bag is short of the SX2100’s 650 g. If you own a Bestway Flowclear sand pump, use Bestway’s figures. Roys prints 240 g for 8.5 kg of sand, 500 g for 18 kg, 700 g for 25 kg, and 1,000 g for 35 kg, which is 28 g per 1 kg. Buying “500 g because that is what Intex sells” copies the wrong document. Model fills for frame pools are on the above-ground filter balls page. If your model is missing from both tables, do not average them.
Windspeed Windspeed filter balls, 1400 g title

Testsieger

Windspeed Windspeed filter balls, 1400 g title
6.0/10about £11.99
View offer

What the marketplace slogans in this comparison actually say

The seven bags print their own sand claims, and two disagree with themselves. Rakiuty at about £3.99 says 200 g equals 4 kg, and both weight lines say 200 g. The other Rakiuty listing, also about £3.99, says 300 g in the title, 200 g in a bullet, and 310 g on the technical line, with the same 4 kg claim. Bomxmon at about £9.99 says 1.54 lb (about 699 g) replaces 75 lb; the technical line is 720 g, so the pack weight agrees and the 75 lb line is still a slogan. Intex 29045 at about £10.99 says 500 g equals 18 kg, coarser than Intex’s model table. Windspeed at about £11.99 says 1,400 g equals 50 kg, and the technical line says 700 g. If you cannot reconcile the title weight, the technical weight, and a published gram table, do not use that bag as your quantity.

Five checks before you order

The pump manual, or the ball brand, has to allow balls. Filterlogic warns that fibre and a damaged strainer are a bad combination, and that flocculant is a separate problem. Read the wash method on the bag you are buying. Intex allows a machine. Bestway and Steinbach say a hand rinse, and they do not treat backwash as the cleaning method. The steps sit on the how to wash filter balls page. Consumer Rights Act 2015, section 9, requires goods to match the description. A title of 1,400 g against a technical line of 700 g is something you can check with scales. Pooltime’s default is not to mix sand and balls unless a maker writes that setup down.

Common questions

How many balls replace the sand in my filter?
Use the sand kilogram in your pump manual, then the gram table for that pump or that ball brand. Intex prints 200 g to 1,500 g by SX model. Bestway prints 28 g of Polysphere per 1 kg of sand. A slogan that says one bag replaces 4 kg, 50 kg, or 75 lb is not either table.
Can I use the same weight of balls as sand?
No. A tank rated for 25 kg of sand does not take 25 kg of balls. Filterlogic’s published example is 700 g of polyballs for 25 kg of sand. Bestway’s published example is 28 g per 1 kg. Matching the sand’s kilogram figure with the same weight of fibre over-fills the vessel.
Do generic bags use the Intex ratio?
Not in this set. Intex 29045 carries model 29045, and its “500 g equals 18 kg” line is coarser than the SX table. The other six bags do not name an SX model. A 200 g claim of 4 kg of sand is not SX925’s 200 g row.
What if the title and the technical weight disagree?
Do not guess which figure was packed. Windspeed’s title says 1,400 g and the technical line says 700 g. One Rakiuty page says 300 g, 200 g, and 310 g. Weigh the bag when it arrives. If it does not match the description, that is a returns question, not a prompt to invent a third weight.
Does a micron claim change the quantity?
No. Quantity is grams for your sand load. Windspeed’s 3–5 micron line is a seller bullet, not a result from this comparison, and it does not tell you whether the bag holds 700 g or 1,400 g. Finer-sounding copy is not a reason to use less media than the table prints.

Related pages

Best filter balls

Filter balls

Intex filter balls sand pump fills for frame pools

How to wash pool filter balls by the brand you own

Filter balls vs sand: weight, wash and public pools

Sources

Public UK sources for pool filtration, taken from the research digest. Listing prices, stars and review counts are from amazon.co.uk on 19 October 2026.

  1. HSE — Swimming pool safety (retrieved 19 October 2026)
  2. PWTAG TN50 — Swimming pool filter specification (retrieved 19 October 2026)
  3. BSI — BS EN 16713-1:2016 domestic pool filtration (retrieved 19 October 2026)
  4. SPATA — Swimming pool filtration factsheet (retrieved 19 October 2026)
  5. Intex support — Fibre ball filtration media (retrieved 19 October 2026)
  6. Bestway UK — Polysphere pool filtration balls (retrieved 19 October 2026)
  7. Filterlogic SFL700P pool filter balls (retrieved 19 October 2026)
  8. Consumer Rights Act 2015, section 9 (retrieved 19 October 2026)