i dont dose anymore since it happend, now the algae/cyano disappear, only few little patch ..Here is my take:
1. Dont chase numbers if corals look good then do nothing. Some of the best tanks like Sanjay are far from zeros on both nitrates and phosphate actually they are very high by "our" standards
2. If you start to run high nutrients (non zero) be a bit generous with light. Nutrients and lighting are positively correlated, that is what I read and heard.
what i do now is feeding coral more often with ab+ , reef roids 3 times a week..add 3 little fish (RG,goby,firefish) and feed them.
No3 - 5-8
PO4 -+ 0.1
dKH 9.2,CA 440, MG 1400, i run two reefled 90 50% blue 5% white on 80G LPS tank.
i see better improvment than before.
but i've lose one acan maxima due to tissue necrosis