Gfo and carbon dosing

[George]

In theory, GFO can absorb all of phosphate in your tank eventually (if you change your GFO frequently). At the same time, the bacterial triggered by carbon dosing also needs both nitrate and phosphate with some ratio (some say 16:1, but I think different strains of bacterial take those 2 in different ratio. Anyhow they always take more NO3 than PO4). If you tank is running out of PO4, carbon dosing won't do you any good.