Hanna Marine Phosphate ULR Pocket CheckerThe HI 774 Hanna Ultra Low Range Phosphate Checker HC (Handheld Colorimeter) provides a simple, accurate and cost effective way to measure phosphate from 0. 00 to 0. 90 ppm. Phosphate is an important parameter to measure in aquaculture and aquariums. Levels that are too high can lead to extensive algae growth, depleted dissolved oxygen levels, and ultimately can be fatal to many types of fish and aquatic life. Designed as a more accurate alternative