There are A LOT of device classes for “scientific” measurements like sulphur dioxide, volatile compounds, sounds pressure… but one that I’ve missed for a long time is accidity/alkalinity (aka, PH).
Every one with a swimming pool, a pond or an aquarium will appreciate greatly, as it’s something we have to monitor closely to add chemicals when needed.
PH is an unitless measurement.
For swimming pools in particular another somewhat commonly used sensor is Free Chlorine (FCL), which is measured in ppm, but those sensor an order of magnitude less common than good old PH.
