Will a slow sand filter take out microcystin toxins more effectively than conventional water filtration (rapid sand filtration) ? It appears as though the answer is yes:
http://www.ncbi.nlm.nih.gov/pubmed/12203961 (information is in the abstract; access to the entire document requires a log in.)
http://www.who.int/water_sanitation_health/dwq/chemicals/microcystin_sections.pdf (its a 3 page document; read the entire document)
http://www.ibg.uu.se/digitalAssets/164/164676_3bojcevska-hristina-jergil-erik.pdf (page 19 and read the entire document)
Removal of Algae and Cyanobacterial Toxins during Slow Sand and Bank Filtration (page 53 “schmutzdecke”)
Slow sand filtration is not used in most water treatment facilities in the U.S. , even though it is more efficient, more sustainable, and less expensive than rapid sand filtration. Slow sand water filtration has been around for hundreds of years and has been shown to work. The city of Salem, Oregon is one of the few cities in the U.S. that uses slow sand filtration.