If detection of Fe+2 is what you need, this is the answer. SenSafe Iron Check II for water quality testing is designed to specifically react with Iron, without interference from other heavy metals that may be present. Say goodbye to dangerous, time-consuming wet-chemical kits that require extensive training and cost. This patented water quality test is a simple dip-and-read test procedure that requires no technical training. Additionally, since there is no glass required to run the test, it is ideal for use in controlled areas. Simply dip one strip into the water for 5 seconds with a back-and-forth motion, remove the strip and shake once to remove excess water, wait 2 minutes for the color to develop, and match with the closest color match to determine your concentration of Iron. Number of Tests: Bottle of 25 Sensitivity: 0, 0.1, 0.3, 1.0, 5.0 ppm (mg/L) Total Test Time: 2 Minutes, 5 Seconds