For a class of 30 students. Truly an excellent way for students of all ages to learn about the water they drink at home and at school! Using nonhazardous, reliable, one-step dip strips, each student tests samples of water to determine the levels of free and total chlorine, pH, total alkalinity, total hardness, nitrate and nitrite, nitrogen, copper, and iron. Testing is simple: just dip the end of the test strip in the water sample, swirl for the specified amount of time, and compare the resultant color with the color chart to obtain the quantitative (ppm) result. Kit contains 30 packets (60 test strips) for each of the 9 parameters listed for a total of 540 tests.