The Hach AquaChek Iron Test Kit Test Strips ensure the longevity of your pool and spa fixtures. Maintaining proper total iron levels can prevent corrosion and rust. This test kit is geared towards testing ferric (Fe3+) and ferrous (Fe2+) forms. Some test strips measure only the ferrous form of iron, whereas ferric iron is actually more common in pool and spa water. This product features a reagent product pillow, sample vial, and test strips to ensure accurate results.