My 120g reef has issues. Getting RTN of my SPS and the only thing I can figure is phosphates. Alk has been rock steady at 9.2, Ca steady at 410ppm. Nitrates are undetectable on Red Sea test kit, and Phosphates were at .16. 2 water changes have it down to .12. I started running GFO in a reactor 2 weeks ago and it is not bringing phosphates down. With Nitrates undetectable my research is telling me to add some nitrates via KN03. The theory being the no nitrates is "starving" the nitrate and phosphate eating bacteria to a level where phosphates will no longer be reduced, nitrates are now the limiting factor. So.... my thought is no nitrates are no good anyway. Why not bump nitrates up to 2 ppm and see if this helps my phosphate problem. What do all you expert reefers think of this? Seem like a reasonable thing to try to get phosphates under control post haste to hopefully combat me watching my price SPS colonies go white in a matter of hours?