Hi guys I am having a problem bringing phosphates down. Recently I just bought a hanna ultra low phosphate checker and found out that my phosphates is around 0.2ppm which is quite high. My nitrates are around 1-2.5ppm. I find this strange because I am using AF NP pro and pro bios. As well as running phosphate minus and carbon in a reactor. I also run an ATS which i harvest almost every month as growth is quite slow. After getting the 0.2ppm reading i changed out my phosphate minus and lower the flow. Have been testing every day and it went down to 0.13ppm. Just tested today and it bounced back up to 0.15ppm. Just some back ground to my equipments. I run a skimz SN123 skimmer and a marine pure block. Everyday using dosing pump to dose NP pro. Kh is at 7DKH, calcium is at 400. Thinking of something drastic like using goodbye po4 to get it down... Im not too sure what else to do.