Kalkawasser replentishes the calcium levels(used by hard corals) while also stabilizing the pH. Stronium and iodine are minerals some reefers add for coral growth. In a FOWLR
I would suggest maintaining a calcium level of 350 for your coraline algae. You could use kalk
for this or you could use one of the many other calcium supplements.
Yes, equipment wise the main change would be a lighting upgrade. Many people start out with a FOWLR
and then move on to corals after getting comfortable with SW
. The only other advice I would give is to choose your fish carefully(research) if you plan on turning your FOWLR
into a reef. Many fish available are not reef safe and you would then either have to trade in the fish or forget the reef tank.