I have my phosphates at .05 to .1, I usually have the opposite wehere I have to remove phosphates. If I'm not paying attention and I take it all the phosphates out on accident bad things happen. If I shut my skimmer off and turn my fuge light off for a day it usually rises within a day or so. You can buy phosphates to dose if you think you need tooAnd what are the phosphate levels you are aiming for? And how do you raise the phosphates when they are to low?