Dissolved Oxygen Test Kit

The Dissolved Oxygen Test Kit employs the classic Winkler titration method, the gold standard for dissolved oxygen measurement in water quality analysis. Dissolved oxygen (DO) is consumed by fish respiration, bacterial decomposition, and chemical oxygen demand; low DO is a common but underdiagnosed cause of fish lethargy, surface gasping, and sudden mortality.

The test involves a three-reagent sequence that fixes and titrates oxygen chemically, producing a colour change from blue to clear at the endpoint. Resolution spans 0–14 ppm at 0.5 ppm increments. The test takes approximately ten minutes and requires careful technique to avoid introducing air bubbles during sample collection.

DO testing is especially valuable in heavily stocked tanks, systems with high organic load, during summer heatwaves when warmer water holds less oxygen, and after any power outage that has stopped aeration.