Target: 0,02-0,08ppm (maximum 0,04ppm/d) Prevent pale corals and bleaching, due to PO4 deficiency. PO4 is being absorbed by the rocks, so it may take a while to level up. (a low range test is required) Concentrate: 0,1ml / 100l = 0,01ppm raise Start dosing: 0,2ml / 100l per day ( keep track with weekly measurements )