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How Wavie works
Wavie measures water in two ways.
- Probes sit in the tank and are read continuously: pH, ORP, salinity, temperature and, with the add-on probe, dissolved oxygen. See Probes.
- Reagent tests run on a schedule. Wavie draws a small sample of tank water into a clear cell, adds a reagent, and measures how much light the coloured result absorbs. These give alkalinity, calcium, magnesium, nitrate and phosphate.
Everything liquid goes through the same three parts: one rotary valve, one pump and one cell. That is what lets an instrument with eight liquid connections fit in a tower 88 mm square.
The valve chooses where liquid comes from or goes to. The pump moves it, in either direction. The cell is where the measurement happens. Details are on the Fluid path page.
- Home the valve. The rotary valve turns until it meets its home switch, so it knows exactly where it is.
- Draw the sample. The valve turns to the sample port and the pump pulls a measured volume of tank water into the cell.
- Take a reference reading. With plain sample in the cell, the photometer records how much light passes through at the wavelength the test uses.
- Add reagent. The valve turns to that test's reagent port and the pump meters in a dose. A stirrer under the cell mixes it.
- Read the colour. The same LED shines through the cell again. The drop in light compared with the reference is the absorbance, which the test converts into a concentration.
- Empty the cell. The valve turns to the waste port and the pump empties the cell into the waste bottle, ready for the next test.
| Parameter | Method |
|---|---|
| Alkalinity, calcium, magnesium | Titration: reagent is added in small steps until the colour changes. Steps 4 and 5 repeat. |
| Nitrate, phosphate | Colour development: a reagent turns the sample a colour whose depth depends on the concentration. |
| pH, ORP, dissolved oxygen | Electrode probes, each on its own isolated input. |
| Salinity | Conductivity probe, converted to salinity. |
| Temperature | Digital temperature probe, also used to correct the other probes. |
The reagent chemistry is in development. See Reagents.