I sell high end General Electric total treatment systems. I would have to test the water to see what you need. Cullingan gets its ass kicked in chlorinated water, heavy metals, and dense organics. It's designed to take out calcium, lime, and some iron. Anything else will go through it and destroy the the softening media in it. To be fair to Culligan, it's ten times better than the cheap infomercial rip offs and crappy box store softners that cleans water like washing your foot with a sock on.
Buying cheap water equipment is like getting a liver transplant in Cuba. Cost less, but what are you getting and would you get it if you knew the risk? If you want it done right, call a pro with an impecible reputation.