Exactly. Thanks. This is a ‘non-domestic’ application shall we say. Measuring something with any buffer capacity at all should negate the water’s pH, so shouldn’t be a problem, but the manufacturers advice still doesn’t sit comfortably with me. But they should know!

Eyesight started going in mid 40s. Still not happy about it.

Long day!

When I was working in Switzerland briefly, people would speak Swiss, German, French and Italian as well as English all in the same breath. I was told they used whatever word was easiest at the time.