I have explained this many times in other threads. I will try to recap a short version here. The bio-polymers in Reef Actif, are long chain marine polymers from sea weed. Just like other forms of carbon dosing, they act to feed beneficial forms of bacteria that then consume PO4 and other nutrients. These bacteria are then consumed by the filter feeding corals, and as a result, get the PO4, and other nutrients, they desperatley need. These long chain marine polymers are a particlarly gentle, very natural, slow acting way to do this. I am not a chemist, so diggin further into the exact chemical process on the molecular level of this, is "above my pay grade" . But those re the basics.