#ed_op#DIV#ed_cl#In a system with a sump type filter, the live rock/sand in both the sump, and dispaly tank provide biological filtration, but what provides the mechanical and chemicat filtrationfiltration?#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#I know that the protiene skimmer plays a part in this, but does it really work to provide allthe mechanical and chemical filtration needed for a system?#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#Robert#ed_op#/DIV#ed_cl#