For approx. 60 measurements. Phosphate strongly promotes algae growth. Thus, it should be regularly checked by means of the sera phosphate-Test and be removed in freshwater with sera phosvec. The phosphate level should be below 1 mg/l (ppm) in freshwater resp. 0.1 mg/l (ppm) in saltwater. Information for use Size Item No. 15 ml 04930