8)

easy to do ph test and calc out just how much carbonate is locked up?

Understanding the Science of Ocean and Coastal ...
Search domain epa.govhttps://www.epa.gov › ocean-acidification › understanding-science-ocean-and-coastal-acidification
The lower the pH value, the higher the acidity of a liquid. Solutions with low pH are acidic and solutions with high pH are basic (also known as alkaline). Prior to the Industrial Revolution, average ocean pH was about 8.2. Today, average ocean pH is about 8.1.

https://duckduckgo.com/?q=...

Thanks for explaining 6th grade science to me, let me return the favor by explaining 6th grade English.

Ocean-acidification doesn't mean "it is turning acidic in absolute terms", i.e. a pH below 7.0.

It means the ocean's pH is shifting towards the acidic end, relatively to its pre-industrial levels.

And as you are correctly saying, that's already happening. 8.2 to 8.1 is exactly that. A shift towards the acidic end. The 0.1 change is already affecting coral reefs and other ecosystems.

Since you're referring to the EPA, here is their dedicated site on the topic:
https://www.epa.gov/ocean-...

As for measuring the CO2 absorption, NOAA has done studies on this in the past and confirmed that the pH is decreasing (i.e. becoming more acidic)

https://www.pmel.noaa.gov/...
https://ocean.si.edu/conse...
https://www.pmel.noaa.gov/...