Recycled glass, a finer cut, and a bed that lasts longer

The best filter glass for 2026

Filter glass is crushed recycled glass used in place of silica sand in a sand filter, and it is one of the few upgrades on this site that changes a measurable number rather than a comfort. The number is the filtration fineness: a sand bed of the usual 0,4–0,8 mm grade holds particles down to roughly 30–40 microns, and glass of the same grade is generally stated at 10–20. The mechanism is not marketing — glass fractures into angular platelets rather than rounded grains, so the bed packs differently and the surfaces carry a slight negative charge that holds fine material. The second figure is the grain size, and this is where a filter is actually specified: most tanks take a coarse bottom layer around 1,0–3,0 mm and a fine top layer around 0,4–1,0 mm, and a single-grade charge is a compromise. Third, the charge weight, which is not the same as sand: glass is less dense, so a filter rated for 25 kg of sand takes roughly 20 kg of glass, and buying by the sand figure overfills the tank. Then bed life, which is the argument for the price — sand is changed every three to five years as the grains round off, and glass is stated by its makers to last considerably longer because it does not round the same way. And backwash water, which glass generally reduces. We compare grain size and grading, stated fineness, charge weight against sand, bed life and origin of the glass.

These parts, one figure beside another

1. 

   Kieskönig Filterglas 20 kg

   Twenty kilograms of filter glass at 0.4–1.6 mm, the widest grading in this family, with a single bullet naming improved filtration of the smallest particles and easier backwashing.

   Grain size

   0.4–1.6 mm

   Grading

   A 1.2 mm spread between smallest and largest — the widest in this family, where the others run 0.5 to 0.7 mm

   Stated fineness

   No figure published. Improved filter performance through filtration of the smallest particles is stated

   Charge weight against sand

   Not published. Supplied as 20 kg, which is the weight two makers here state as equivalent to 25 kg of sand

   Bed life

   Not published

   Glass origin

   Not published — neither new nor recycled glass is stated

   Amazon reference

   B0B6HVPG8Y (one reference across 1 Amazon marketplace)

   EAN

   4251199734481

   • Names the backwashing advantage — a smoother surface releasing dirt more easily — which is what glass is actually bought for
   • A 20 kg sack, which is the charge weight two rivals here state as the sand equivalent
   • One bullet, and five of the six figures on this shelf are absent

   Best for: A filter whose manual specifies a broad grading, where price per kilogram decides

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2. 

   poolomio Nature Works Filterglas 20 kg

   Twenty kilograms of filter glass made from new white glass — explicitly not recycled — at 0.6–1.2 mm, published as reusable for up to ten years and equivalent to 25 kg of sand.

   Grain size

   0.6–1.2 mm, stated usable in all common sand filter systems at fine and coarse grading

   Grading

   A 0.6 mm spread

   Stated fineness

   No figure published. Filters even the smallest particles, stated, with MC2 anti-compaction technology preventing clumping and organic deposits

   Charge weight against sand

   20 kg of glass replaces 25 kg of sand — 20 % less material, published

   Bed life

   Up to 10 years, stated. Two other makers in this family publish about 3–4 years and 20–30 % longer than sand

   Glass origin

   Naturally pure white glass from glass industry production surpluses — explicitly stated as not recycled glass

   Amazon reference

   B00KFGV7F6 (one reference across 5 Amazon marketplaces)

   EAN

   4250528801870

   • States its glass origin outright, and states what it is not — no recycled glass
   • Publishes the charge conversion: 20 kg of glass for 25 kg of sand
   • Its ten-year figure is roughly triple what two other makers in this family publish

   Best for: A filter being converted from sand, where the glass is expected to outlast several sand changes

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3. 

   Bayrol Eco Filterglass Plus Grade 1

   The only product on this shelf to publish a fineness in microns: 5 µm, stated to filter 30 % more than conventional sand. Twenty-five kilograms of recycled glass at 0.3–1.0 mm, the finest grading here.

   Grain size

   0.3–1.0 mm — the finest bottom end in this family

   Grading

   Grade 1, a 0.7 mm spread

   Stated fineness

   5 µm, stated to filter 30 % more than conventional sand — the only micron figure in this family

   Charge weight against sand

   Not published. Supplied as 25 kg

   Bed life

   Not published

   Glass origin

   Recycled glass, stated

   Amazon reference

   B07462WX12 (one reference across 5 Amazon marketplaces)

   EAN

   4002369966306

   • The only filtration fineness published anywhere on this shelf — 5 µm
   • The finest bottom-end grading here at 0.3 mm
   • No bed life published, where three rivals here make a durability claim

   Best for: A filter where fine particulate is the problem and the bed is judged on what it catches

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4. 

   Duraol ECO Filterglass Grade 1

   Twenty-five kilograms of recycled filter glass at 0.3–1.0 mm, published as lasting 20–30 % longer than quartz sand — about three to four years — and needing 20 % less material.

   Grain size

   0.3–1.0 mm — joint finest bottom end in this family

   Grading

   Grade 1, a 0.7 mm spread

   Stated fineness

   No figure published. Improved filter performance is stated

   Charge weight against sand

   20 % less glass needed than quartz sand, published. Supplied as 25 kg

   Bed life

   20–30 % longer than quartz sand — about 3–4 years, stated. Another maker in this family publishes up to 10 years

   Glass origin

   Recycled glass, stated

   Amazon reference

   B00ANW7QAW (one reference across 5 Amazon marketplaces)

   EAN

   4260215487416

   • Publishes a bed life as a duration AND as a percentage against sand, so the claim can be checked both ways
   • Publishes the 20 % charge reduction against quartz sand
   • Its three-to-four-year figure is roughly a third of what another maker here publishes for the same material

   Best for: A buyer who wants a durability figure they can hold the maker to, rather than a round decade

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5. 

   Paradies Pool Nature Works Hi-Tech Filterglas

   Twenty kilograms of filter glass made from 100 % pure flat glass at 0.6–1.0 mm, stated free of contamination and preventing germ and biofilm formation.

   Grain size

   0.6–1.0 mm

   Grading

   A 0.4 mm spread — the narrowest in this family

   Stated fineness

   No figure published. Filters even the smallest particles, stated

   Charge weight against sand

   Not published. Supplied as 20 kg, which two makers here state as equivalent to 25 kg of sand

   Bed life

   Not published

   Glass origin

   100 % pure flat glass, stated. A quality product from Europe

   Amazon reference

   B09VBWJHX1 (one reference across 3 Amazon marketplaces)

   EAN

   4251751612929

   • The narrowest grading in this family — a 0.4 mm spread, so the bed is uniform rather than stratified
   • Names flat glass specifically, which is a defined industrial stock rather than mixed cullet
   • No bed life, no fineness figure and no charge conversion

   Best for: A filter specified for a narrow uniform bed rather than a graded one

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6. 

   Pool-Profi24.de Premium Clear Crystal Filterglas

   Twenty-five kilograms of filter glass at 0.5–1.0 mm, described as durable, environmentally friendly and efficient. The grading and the weight are the only figures published.

   Grain size

   0.5–1.0 mm

   Grading

   A 0.5 mm spread

   Stated fineness

   No figure published. Efficient filter performance for clear water quality is stated

   Charge weight against sand

   Not published. Supplied as 25 kg

   Bed life

   Not published. Described as long-lasting

   Glass origin

   Not published — neither new nor recycled glass is stated

   Amazon reference

   B0F22SKSH2 (one reference across 4 Amazon marketplaces)

   EAN

   4250839153057

   • A 25 kg sack at a mid-range grading, which suits a filter specified in sand quantities
   • 0.5–1.0 mm sits between the fine and coarse ends of this shelf without committing to either
   • Four of the six figures on this shelf are absent

   Best for: A filter whose manual specifies a 0.5–1.0 mm bed and where the sack weight matters

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7. 

   SAXONICA AFM Filterglas Grade 1

   Twenty-one kilograms of activated filter material made from recycled green and brown glass at 0.4–0.8 mm, stated to last 20–30 % longer than quartz sand and to improve filter performance by up to 30 %.

   Grain size

   0.4–0.8 mm — the same grade as the commonest pool filter sand

   Grading

   Grade 1, a 0.4 mm spread — joint narrowest in this family

   Stated fineness

   No figure published. Filter performance improved by up to 30 %, stated

   Charge weight against sand

   Not published. Supplied as 21 kg, which sits between the 20 kg and 25 kg sacks on this shelf

   Bed life

   20–30 % longer than quartz sand, stated. Another maker in this family puts that at about 3–4 years; a third publishes up to 10 years

   Glass origin

   Recycled green and brown glass pieces, activated. The only listing here to name the colours

   Amazon reference

   B0BSR7BNHQ (one reference across 4 Amazon marketplaces)

   EAN

   4061888019603

   • The only glass here supplied at 0.4–0.8 mm, matching the commonest sand grade directly
   • Names the source down to the glass colours — recycled green and brown
   • No fineness figure, no charge conversion and no duration behind its 20–30 % claim

   Best for: Swapping a 0.4–0.8 mm sand bed for glass without changing the grading the filter was built around

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