What do you mean they can't check them
In response to John's post about this subject, I think enough credit is not being given to our tech folks. These are the same people who mastered the art of fuel testing, right. And it is a complicated sampling, mixing with multiple reagents and reading IIRC color change, as well as reading a conductivity meter. And maintaining sampling containers properly to avoid cross contamination.
And someone thinks that these same folks can not read a simple light meter??
Come on who is zooming who?