Need Help with High Phosphates

[Enigma]

I used Phosbuster Pro to knock my phosphates down (in addition to changing my ROWAphos). But! I dosed very conservatively: 1/4 dose or less, two days apart, and I watched my phosphate readings closely. It is one of those things that seems to trigger tank crashes when a whole dose is used at once: especially when a big reduction is required.