I have the same (identical?) problem.
My 75 tank has 1 hippo tang, 1 foxface, 1 dottyback, 2 clown, 2 hermit crabs and 1 shrimp. All readings fine.
I have seen the white bubbles (not small dots) on my h-tang for about one month and she is the only one who has it. I did not treat the tank with...