Depends on what corals you want to keep...
One thing I don't really like about kalk is that if your evaporation rate vary a lot you will struggle to hit stable parameters
Unless you use kalk and 2part together where kalk provides bulk of the requirements and you use 2part to hit your target parameters
But if you only going to keep a some softies, lps then both options will work
One thing I don't really like about kalk is that if your evaporation rate vary a lot you will struggle to hit stable parameters
Unless you use kalk and 2part together where kalk provides bulk of the requirements and you use 2part to hit your target parameters
But if you only going to keep a some softies, lps then both options will work