Sorry about that... I often forget that any hobby develops it's own "lingo" and sometimes what is clear to one person isn't to another!
If you're algae, then nitrates and phosphates are "nutrients", and they ARE a good thing (for the algae)! But in our book, they're bad things and referred to as "excess nutrients". All depends on what side of the battle you're on! And the never ending battle for us is to give your tanks enough nutrients to thrive, but yet not enough to fuel the nuisance algae and cyanobacteria. Any food that goes uneaten in a tank will eventually break down into nitrates and become... excess nutrients.
The calcium and alkalinity numbers you mention are just elements in the saltwater, and not necessarily "nutrients". While they ARE nutrients - in a way - for coral, folks don't normally refer to them as "nutrients".