The gurus will probably be around to answer more in depth shortly, but I believe hardness as CaCO3 is related to the Ca2+ and Mg2+ concentrations as:
Hardness as [CaCO3] = 2.5*[Ca2+] + 4.11*[Mg2+]
So even though you don't know the exact ratio between the calcium and magnesium concentrations, the maximum these could be would be 13.1 ppm Mg2+ (with 0 ppm Ca2+) or 21.6 ppm Ca2+ (with 0 ppm Mg2+). In either case, you have soft water.
It looks almost like lime softened water. It's definitely appears to be decent brewing water. You'll obviously want to get rid of the chlorine. I don't know how high of a level 75ppb for iron is though. You'll need to add more calcium and some acid for many paler beers.