| Absorbance |
How much light a sample soaks up. A darker colour absorbs more. Wavie measures it to work out a concentration. See Optics |
| Alkalinity |
The water's ability to resist changes in pH, mostly from carbonate and bicarbonate. Corals use it to build their skeletons |
| BNC |
The twist-lock connector used for the pH, ORP, salinity and dissolved oxygen probes |
| Buffer solution |
A liquid with a known, stable pH, used to calibrate a pH probe |
| Calibration |
Teaching an instrument what a known value looks like, so its readings come out right |
| CAN bus |
A sturdy wired network, the kind used in cars. Wavie uses it to talk to other ReefMetrics devices. See Expansion |
| Conductivity |
How easily water carries electricity. Salty water conducts better, so conductivity gives salinity |
| Cuvette (cell) |
The small clear container where the sample and reagent are measured |
| Dark reading |
A light reading taken with every LED off, subtracted from the others to remove stray light |
| Dissolved oxygen (DO) |
How much oxygen is dissolved in the water |
| Galvanic isolation |
Separating two circuits so no current can flow between them. It keeps the probes from interfering with each other |
| Manifold |
The part where the eight tubes of the valve join into one line. See Fluid path |
| ORP |
Oxidation-reduction potential: a measure, in millivolts, of how oxidising the water is |
| Peristaltic pump |
A pump that moves liquid by squeezing a tube with rollers. The liquid only touches the tube |
| Photometer |
The part that measures how much light passes through the sample. See Optics |
| Pinch valve |
A valve that opens and closes by squeezing a flexible tube |
| Reagent |
A chemical that reacts with the sample to produce a colour Wavie can measure. See Reagents |
| Salinity |
How much salt is in the water, in parts per thousand (ppt) |
| Specific gravity (SG) |
Salinity expressed as the water's density compared with fresh water; around 1.026 for a reef |
| Stepper motor |
A motor that turns in exact steps, so Wavie knows precisely how far it has moved |
| Titration |
Adding a reagent in small steps until the colour changes; the amount needed gives the result |
| Wavelength |
The colour of light, measured in nanometres (nm). Wavie uses 540, 615 and 880 nm |