Filter Aid
Many materials such as paper pulp have been used to cut a poorly
filtering material with something that filters well, but the best
filter aids are Perlite, an exploded rock, and diatomaceous earth
that is the skeletons of prehistoric diatoms. This photo taken
from an ad in a magazine shows one skeleton greatly enlarged.
This structure filters wonderfully, and the pores in the
skeleton take up greasy materials. Mixing this nice material
with materials that filter very poorly usually results in quite
good filtration.
