It'll eventually settle out. I have had Krausen stick around for very long periods of time and micro is right it's mostly about the yeast choice. You are hitting 75% attenuation so it sounds like all is going well. What I have learned is that you'll see all sorts of weird stuff, just trust your hydro readings! And before worrying about something going wrong, let the beer completely finish (I mean all the way through aging) before casting judgment.