Replacement foam set for the blagdon inpond all in one 3000r pack contains course and medium filter pads one of eachr the coarse foam is black and the medium foam is green these should be replaced as they get too dirty or start to degrader on a regular basis the foams should be removed from the inpond filter and rinsed in dirty pond water the ceramic media should also be cleaned regulary in dirty pond water to prevent blocking the filter