This kit uses a fast, simple and efficient technique to measure phosphate levels from 0-10 ppm (higher if samples are diluted prior to testing). Simply snap one of the self-filling test ampules in the sample cup, wait four minutes, and directly compare the test ampule to a set of color standards. Kit includes color standards, sample cup, 30 test ampules, and detailed instructions. A refill kit of 30 test ampules and activator solution is available separately. Color standards have a shelf life of two years or more if protected from excessive light exposure.