I do have a couple leaks. Sorry I had to look up "cavetating". You learn something new everyday. That's why it is so fun.
Anyway, the problem may be that:
1. I have a leak in the plumbing
or

2. the pumps output is too high creating this Cavetating effect therefore creating the air bubbles. The document I saw says that Cavetating causes a boiling effect on the water output.

Correct?