I found Elimi NP very effective (1.2 ml /110g). I stopped the GFO and my phosphates did go up to 0.2-0.1 ppm and my nitrares are around 5 ppm. More importantly, my corals are happy . I also dose KZ sponge power to promote sponges growth. I have a lot of very heavily fed fish, no water changes and corals are mostely lps (I have two small sps corals that also started growing). When my phosphaye go below 0.1 I will start adding the NP bacto-balance mixed with the elimiNP.