neo phos

Hey guys, some Phos questions. So 0 phos in my tank lately (hanna chekcer), dinoflagellate outbreak- covered my sand, rocks, corals etc. Turned lights off in my tank 3 days, dosed 15 ml of NeoPhos for 250g. (According to directions, 19mls would have given me a level of 0.02 for the tank). Hanna...