Thanks for posting.
Does the Fluidyne unit use energy besides the circulating pump. It looks like the magnets are permanent and not electric.
I believe I interpret that your make up tank had a steam injection. This sounds to me like it is used as a de-aerator, essentially pre-heating the water which will also vent off dissolved oxygen.
I found it interesting that the Fluidyne system discussed it's ability to precipitate hardness scale. It specifically mentioned calcium carbonate. It didn't say what happened to the "solid white crystal", although it sounds like it would pass into the boiler, not settle on tubes and form a hard scale, but be removed with the blowdown.
I have to question some of the stats presented by Fluidyne. Your boiler produces about 30,000 lbs of steam per hour, making it a smaller industrial boiler, but still a decent size. Pre Fluidyne, the blowdown was 50% and the chemical usage was 200 lbs per day. If this is accurate, both of these are insanely high, although perhaps possible if the system uses a very high percentage of make up water. Post Fluidyne, the blowdown was 4%, which is normal even with chemical use. It does not state weather you currently use any chemicals, although, I am assuming not.
I am one of those sceptics - basically a chemical guy, although I never sold them, however I used them and it is all I understand. However, always willing to learn something new. You say the boiler is very clean upon inspection with no scale or rusting. This is the proof of the pudding. However for me, I will stick with what I know. LOL.