filter designed to use diatomaceous earth (D.E.) as the filter medium; the D.E. is added through the skimmer with the pump on, which takes the D.E. and deposits it on a grid; the D.E. then becomes the filter medium
filter designed to use diatomaceous earth (D.E.) as the filter medium; the D.E. is added through the skimmer with the pump on, which takes the D.E. and deposits it on a grid; the D.E. then becomes the filter medium