Yes, but a simple one time test did answer the question so we know for the future.

It's fine to test, and few do it until there's a problem.
Not cause they are curious and "want to learn" as so many claim.

If nutrients really are something folks want to learn about, and algae etc, why don't more induce algae, or try to on nice clean algae free tanks and measure the nutrients then?

If you do not have a control, it's really just guessing.
you can only do so much with observations alone.


Regards,
Tom Barr