Your tank is coming along very nicely. Do you mind if I ask what kind of salt you're using? Just wondering since you're thinking of dosing with the kalk (calcium, I think). It might be better to do the calcium test first and see where you stand in that respect. I noticed when I switched salts from Instant Ocean (NOT the IO Reef Crystals which are very good too) to Oceanic my calcium improved considerably! It may be just coincidental, but I've been using Oceanic since and my corals seem to really love it. Just a thought, rather than dosing. That with a consistent running skimmer and regular water changes and maintenance seem to do the trick for my 46gal bowfront.
Very nice start...I love to see progression like that
Lisa