Technical
Water Filtration Pebbles: Sizes and Applications
In filtration, grading and cleanliness are the specification. Appearance is irrelevant.
Buy Pebbles editorial team · Reviewed by the Buy Pebbles supply desk · Published · 5 min read
What the stone does
In a filter bed, graded stone supports the finer media above it and distributes flow evenly across the underdrain. Without it, media migrates into the drainage system and flow short-circuits through channels.
Typical layering
Beds are usually built coarse at the base and progressively finer towards the top, each layer sized so the material above cannot pass through it. Exact schedules come from the plant designer.
Cleanliness matters more than looks
Silt and organic content reduce filter performance from day one. Specify washed material and say clearly that the order is for filtration rather than landscaping.