Pool Filter Media Calculator
Tell us your filter tank diameter and we’ll work out exactly how much silica sand, crushed glass or AFM you need — in kilograms and 20 kg bags.
Optional — overrides the diameter estimate if your filter has a label.
Enter your tank diameter to get started
Most residential pools use a 450–750 mm filter.
Before you load your filter — read this
Check the data plate first
Always check the manufacturer's data plate on the side of your filter tank for the exact sand-capacity rating. That number trumps any calculator.
Use the right grade
Only use #20 silica sand (0.45–0.55 mm), recycled crushed glass, or genuine AFM. Never play sand or beach sand — it can damage your filter and plumbing.
The 2/3 rule
If the label is missing, fill the tank no more than two-thirds full. Leave the top third empty so water can pool and distribute evenly across the media bed.
Water cushion before media
Fill the tank with 15–30 cm (6–12") of water before pouring media in. This cushions the impact and protects the laterals at the bottom.
Grade split on bigger tanks (>21")
For glass and AFM in tanks larger than 21", split your purchase into ~25% Grade 2 coarse at the bottom and ~75% Grade 1 fine on top. The calculator above does this split automatically.
Round up bag counts
Bag counts are rounded up — it is better to have a little spare than to be short mid-changeover. Unused media stores indefinitely if kept dry.