Macherey-Nagel test strips for total chlorine at low concentrations, in one presentation.
91361
A semi-quantitative test strip for total chlorine at low concentrations. Dip it, wait the stated time, and compare the pad against the colour scale on the tube.
Sometimes the requirement is to prove chlorine is nearly gone rather than present: rinse water before a membrane, dialysis feedwater, an aquarium being filled from the tap. At those levels an ordinary chlorine strip reads zero long before the chlorine is actually harmless.
A strip gives a range, not a figure. That is enough for the great majority of decisions — dose or do not dose, discharge or hold, keep running or stop — and it gives the answer where the sample is, in about a minute, with no instrument to calibrate and nothing to carry back to a laboratory.
When a number has to be defensible — a regulatory report, a dispute, a limit you are close to — a photometer or a laboratory method is the right tool. The strip's job is to tell you whether you need one.
Total chlorine includes chloramines, which is the point: chloramines pass through a free-chlorine test and still destroy a membrane.
Supplied in one presentation.