Independent comparisons. We may earn from shop links. More info

Coarse or fine pond filter foam

Updated: 22 October 2026

The pump is labouring and the finest pad is the first thing the water hits. Coarse or fine pond filter foam is the order of those grades, and the colour codes that do not travel from one brand to the next. Water should meet the most open pad at the inlet. First means that inlet side. The twelve listings are on the [pond filter mats comparison](/hub/garden-ponds/pond-filter-mats). Peter F. read those amazon.co.uk pages on 21 October 2026 and did not run a lab test. A qualifying purchase can earn us a commission at no extra cost to you.

The pump is labouring and the finest pad is the first thing the water hits. Coarse or fine pond filter foam is the order of those grades, and the colour codes that do not travel from one brand to the next.

Our top picks

Borlech Borlech 20 PPI foam 47 × 47 × 2 cm

Best overall

Borlech Borlech 20 PPI foam 47 × 47 × 2 cm
8.0/10about £7.99
View offer
INGVIEE INGVIEE foams for 1400EF and 1400EF+

Rank 2

INGVIEE INGVIEE foams for 1400EF and 1400EF+
7.5/10about £13.99
View offer
Unbranded Black 20 PPI foam 50 × 50 × 2 cm

Rank 3

Unbranded Black 20 PPI foam 50 × 50 × 2 cm
4.0/10about £7.99
View offer
On this page
  1. 1.Lower PPI is the open pad
  2. 2.Coarse at the inlet, fine after
  3. 3.Blue, white and yellow are brand labels
  4. 4.One grade on the listing you can check

Lower PPI is the open pad

PPI means pores per inch. eFoam sets out bands of about 10, then 20, then 30, then 40, and says colour does not indicate the grade. A lower number has larger holes. A rule of thumb beside those seller bands is about 10 coarse, 20 medium-coarse, 30 medium-fine, and about 45–50 fine. eFoam’s 5–10 year life claim is a seller statement. The Borlech sheet is £7.99, stated 20 PPI, 4.5 from 314 reviews. The unbranded black sheet is the same price and grade, 3.6 from 19 reviews. Either can fill a single chamber. Neither is a coarse-plus-fine system. How to choose the format is on the pond filter foam buying guide.

Coarse at the inlet, fine after

Put the coarsest pad on the inlet side, then a medium pad if you have one, then the finest. Pond Life’s forum puts it in that order. A stack fitted backwards blinds the fine cells with solids the coarse pad should have held. Turn the stack around before you buy a bigger pump. If the flow falls, Hozelock suggests two coarse foams and one medium, rather than coarse, medium and fine. Leave aside a Hozelock spare line that says fine to coarse. Water meets coarse first. The rinse, in pond water, is on how to clean pond filter foam.
Borlech Borlech 20 PPI foam 47 × 47 × 2 cm

Testsieger

Borlech Borlech 20 PPI foam 47 × 47 × 2 cm
8.0/10about £7.99
View offer

Blue, white and yellow are brand labels

All Pond Solutions says blue is coarse and goes first, and white is fine. Those cleaning intervals belong to that brand’s aquarium foams. Velda’s map is different: white is fine, blue is medium, and black is coarse. If the seller has not tied a colour to a PPI, the dye is only a dye. INGVIEE’s £13.99 bag for the 1400EF and 1400EF+ is six white floss pads and three blue coarse foams. The £16.99 bag is the same mix for the 1000EF+. Blue faces the inlet. The SunSun pair at £14.49 is yellow fine and blue coarse, and a bullet names the CBF-200T. A black sheet with no PPI is not coarse merely because Velda paints coarse foam black.

One grade on the listing you can check

Buy a page that states one PPI, one thickness, and one size. The Borlech sheet does that. The polyurethane sheet at £8.09 does not: the size line says 35 PPI and 4 cm, and the bullets also offer 20, 35 or 50 PPI. A soak that restores thickness does not tell you the pore count. A 50-micron claim is not a PPI. The white floss at £10.99 uses that bullet and also prints 3 cm against 0.3 cm. The eight-layer pad does not state a PPI, so it cannot be the coarse or the fine step in a stack you are building by number. If you have two generic sheets, use the lower PPI at the inlet. Wool after the foam is on pond filter wool or foam.

Common questions

What does PPI mean?
PPI is pores per inch. eFoam uses that definition for aquatic foam. More pores in each inch means a finer pad. Fewer pores means a coarser pad that stays open longer. A colour, a micron claim, or the word fine is not a PPI.
Which number is the coarse one?
The lower number. About 10 PPI is coarser than 20, and 20 is coarser than 30, on eFoam’s seller bands. A 20 PPI sheet is medium-coarse. A listing that offers 20, 35 and 50 on one page has not told you which of those three you will receive.
Does blue always mean coarse?
On All Pond Solutions foams, blue is coarse and white is fine, and blue goes first. On Velda’s map, blue is medium and black is coarse. eFoam says colour does not indicate the grade. A yellow pad in the SunSun pair here is the fine one on that listing, not a universal code.
What happens if the fine pad is first?
The fine cells fill with the solids the coarse pad should have caught, and the pump works against a blocked mat. First is the inlet side of the housing, not the top sponge in a pile. Turn the order around before you replace the pump.
How do the white and blue pads in a set get stacked?
On the INGVIEE bags, blue is the coarse piece and white is the floss, so blue faces the inlet. That follows All Pond Solutions’ own note, on the model in the title: 1400EF and 1400EF+ at £13.99, or 1000EF+ at £16.99. The SunSun pair is blue coarse and yellow fine, and the bullet names the CBF-200T.
Is 50 microns the same as a PPI?
A micron figure is a particle size. PPI is a count of pores. The £10.99 floss uses a 50-micron bullet and contradicts itself on thickness. It is not a 50 PPI foam, and there is no Customer Reviews line on that listing.

Related pages

Pond pump comparison

Pond filter mats

Best pond filter foam for the chamber you can measure

How to choose pond filter foam by the model suffix

Pond filter wool or foam inside this filter chamber

How to clean pond filter foam without a full strip

Sources

Public UK and maker sources from the research digest, used for this page in October 2026. Prices, stars and review counts are from the twelve amazon.co.uk listings in the comparison snapshot of 21 October 2026. A reviewer’s clearer-water line is not a measurement of ammonia or nitrite. eFoam’s PPI bands are seller guidance, not a measured life for foam in a UK pond.

  1. Water Garden, how to clean pond filter foams (retrieved 21 October 2026)
  2. All Pond Solutions, blue versus white filter foams (retrieved 21 October 2026)
  3. Hozelock, filter maintenance (retrieved 21 October 2026)
  4. Practical Fishkeeping, buying the right pond filter (retrieved 21 October 2026)
  5. eFoam, aquatic filter foam (retrieved 21 October 2026)
  6. Blagdon, filter maintenance (retrieved 21 October 2026)
  7. GOV.UK, discharges to surface water and groundwater (retrieved 21 October 2026)
  8. Consumer Rights Act 2015, section 22 (retrieved 21 October 2026)