Soil sensor FAQQWhy do the values for moisture percentage by volume only go up to 60% for ordinary soil? / What is the output when the moisture percentage by volume exceeds 60%?

Volumetric water content is the percentage of moisture of a given volume. Soil volume consists of solid components, moisture, and air.
Solid components account for approximately 40% of typical soil, so the volumetric water content would never exceed 60%.
This is why the maximum output is approximately 66%.
Solid components are only a few percent of artificial soils like rock wool and coco peat, so the maximum output is 100%.