I use the Salifert teat kits. I cant distinguish on the phos. The color is hard to read at low levels.BTW, salifert test kits for phos and nitrate arrive today. I am having an issue with cyano and SPS polyp extension. Calcium is 410, alk 9 and mag is 1330 (Those numbers are suspect because of the test kits but I don't think they are far off).
Ammonia alert shows fine. (Keep in mind I don't tell the colors, Sherry looks at the tests for me)