I finally got around to using Nature's Answer for the first time (still have 2 bottles of Rezblock I haven't used). I put 9 or 10 drops in my Mobius Ion and can say that it works great. Cheers.
That's a bit more than I've been using.
I've been using between 6-8 drops, and that's in my clear matrix, which holds about twice as much as the ion. (My water is pinkish, not reddish if that makes sense.)
It's been working really well.
I've been using my clear matrix as my daily driver for over a week now, changing the water every few days.
I've gone through maybe 6 water changes, and given it a rinse-out with hot water 2 or 3 times.
Every hot water rinse, it's been coming out very clean
Even the inside of the downstem cleans out really easily, but I do make a point to lightly blow into the bub enough to coat the downstem once per session.
I'm starting to notice some clouding in the mouthpiece/neck, and a small bit of clouding at the water level, but a PBW soak will take care of them easily.