The test kit (TK0159) does not provide accurate answers.

The advantage of TK0159 is its ease of use and low cost per test. For the most accurate results, the drop count kit should be calibrated against a UV-digestion test for OP. Once calibrated to your system and product, TK0159 can be used to monitor changes in OP concentration on a more frequent basis without running costly and time-consuming UV digestions.