It'd be easy for one of us to test gentle shake vs vigorous (for PO4) but,,, uhh,,, I ain't gonna volunteer.I shake the S out of both Hanna phosphate and nitrate. Didn’t realize that po4 was supposed to be a gentle shake. I wonder what the difference is in the results.
*plus, after vigorous NO3 shake, I enjoy the relaxed PO4 shake ... doh!
I always wondered if it had anything to do with the fact that the Phosphate timer is less (than nitrate) so less time for bubbles to settle down (that might interfere with photo receptor reading),,, but now I'm just talking out of my ___ and have no idea.