Here is a table showing the amount of sand that should be poured in each sand filter size. Make sure to measure the diameter of your filter, so that you can easily calculate how many pounds of sand to add.

Sand filters generally start at around 16 inches in diameter. For a 16-inch sand filter, you should expect to add around 100 lbs of sand. For every inch in diameter larger than 16 inches, you add an extra 25 lbs of sand until you reach 20 inches. From 20 inches, you add 50 lbs for every 2 inches in diameter until you reach 24 inches. From 24 inches, you add 50 lbs for every 3 inches until you reach 27 inches. For every 3 inches above 27 inches, you will add 150-200 lbs. The largest sand filters are generally around 36 inches.

Here is a helpful chart:

Diameter of the Tank	Pounds of Sand to Add
16 inches	100 lbs
18 inches	150 lbs
19 inches	175 lbs
20 inches	200 lbs
22 inches	250 lbs
24 inches	300 lbs
27 inches	350 lbs
30 inches	500 lbs
36 inches	700 lbs

This table will not translate to every pool pump model. Some may have slightly different volumes, and some will require more sand than others. So always check your model’s instructions first.

If doing all that math makes your head hurt, here’s a calculator I put together to figure out how much sand you need to add based on your tank diameter.