First water change now pump is just shooting out thousands of tiny bubbles.

Some skimmers will do this after water changes, so it should go away on its own. My remora does it too, after an hour or so, it goes away.

About "microbubbles" the term micro is very often misused...Micro means it's so tiny you can't see it unless magnified. Think of it this way, when waves brake in the ocean, there are thousands/millions of small bubbles going all over the place, fish dont mind, so don't worry, those bubbles are not micro enough to bother your fish. My two centavos. laters.