The Hanna HI701 Free Chlorine Checker® HC is a pocket-sized handheld colorimeter bridging the gap between basic test strips and professional photometers. Using the EPA-approved DPD method, it digitally measures active free chlorine from 0.00 to 2.50 ppm with 0.01 ppm resolution.
How It Works & Testing Steps
Unlike manual color charts, the device uses a fixed wavelength LED and silicon photodetector to eliminate human error and provide accurate numerical readouts.
- Zeroing: Fill a clean cuvette with your water sample, insert it into the checker, and press the button to zero the instrument.
- Reagent Mixing: Remove the cuvette, empty it, and add the precise, pre-measured DPD powder reagent (e.g., HI701-25). The sample will turn a pinkish hue.
- Reading: Insert the reacted sample into the meter, press and hold the button for a built-in countdown (typically 1 minute), and read your precise free chlorine concentration.
