How each kind of instrument works, what interferes with it, and how to keep it reading true. These pages apply whatever the make or model; see Equipment for specific models.
| Measurement |
What it tells you |
| pH |
Acidity or alkalinity of the water |
| ORP |
Oxidizing strength, commonly used to control oxidizing biocide |
| Conductivity |
Dissolved solids, and so when to bleed |
| Fluorescence (PTSA) |
Treatment product concentration, from a fluorescent tracer |
| Turbidity |
Suspended solids, as cloudiness |
| Corrosion Rate |
How fast metal is corroding in the water |
¶ Level, pressure, and flow