This is certainly true, but amount matters. If its 300 years then we have a problem, if its 3000, maybe not so much. Articles like this do not help give perspective.

Actually since ocean acidification provides a chemical power source for protozoa, we probably only have a year or two before one of the species adapts and brings it back to it's previous level by harvesting the energy in it. That will allow one of those species to rapidly spread, which is exactly what we want in this case.

Trying to fix it using any kind of non-self-replicating technology is, imho, a non-starter.