The JBL ProAqua Test PO4 Phosphate sensitiv is designed fro measuring and routinely controling the phosphate content in saltwater and freshwater within the range of 0.05-1.8 mg/l (ppm). The compensation method developed specially by JBL allows precise and reliable results to be obtained even in moderately discoloured aquarium water e.g. caused by peat filters and disease treatment. Through the high sensitivity of the JBL test PO4 sensitive the impending danger of excessive phosphate levels can be recognised at e very early stage and suitable preventative measures to be taken in good time.In the natural enviroment phosphate, a vital plant nutrient, only occurs in very low concentrations. The average levels are about 0.01 mg/l in freshwater and about 0.07 mg/l in saltwater. In an aqaurium, the main sources of phosphate in the water are digestive processes of the fish and food residue. Under unfavourable circumstances phosphate levels can reach up to 100 times or more above the natural le