Thanks for stepping in and sharing your thought process behind this change. Obviously it hit a nerve. I don't doubt that you did this for good reasons, but that doesn't mean it was correct. The Kalk change especially deserves a BRS investigates. I firmly believe this change is reef fantasy.Hi,
The calcium hydroxide had the most significant increase in quality and in a whole different class of source materials. Functionally it is denser, and you can use a small amount less to achieve the same results. It is also less talc-like or "poofy" meaning it is harder to get airborne and breath, so I think it is fair to consider it safer to use. This also contains ultra-low organics and impurities, most specifically ultra low aluminum. I understand that many do not believe a higher quality material is needed because kalk solution will settle out many impurities but that's not the case with all impurities, and that also implies you never let the pump suck concentrated impurities off the bottom. It's just better if it was never there in the first place. I also think ultra low impurities in our additives is more important than ever in a world where many reefers are doing fewer water changes than ever before.
I think you can put together a test of old Kalk and new Kalk that shows the results in a reef tank after ~3-6months. Take 2 systems, dose kalk in both and after 6 months get an ICP test. If what you say is true the results should be obvious. Maybe dose large amounts over a shorter timeframe and let precipitation takes it course (though that might be skewed vs coral growth).
Regarding sucking concentrated impurities off the bottom, is there any proof that these will dissolve in a tank? I'd assume they stay solids and have no effect on water quality.