The Pondwater Tour is a great introduction into the study and measurement of changes in the water quality of a lake, stream, pond, aquarium, or even a fish bowl. Each student on the Pondwater Tour conducts water quality tests for pH, dissolved oxygen, nitrate, and ammonia using safe, simple TesTabs® reagent tablets. Students test variables and investigate natural processes that create changes in water quality over time. Tablets and sample test bags for 50 students. Grades 4 to 8 / 50 Students. Shipped directly from supplier.