A softener treats hardness
Ion-exchange softening reduces calcium and magnesium hardness, which can form scale. It is a whole-home treatment for the connected plumbing, but it is not a universal contaminant filter or disinfectant.
Activated carbon addresses applicable taste and odor
Carbon treatment can help with applicable chlorine taste and odor concerns. Performance depends on the specific media, flow rate, contact time, and water conditions. Ordinary activated carbon does not establish chloramine reduction; request model-specific support for a particular treatment claim.
RO is a kitchen drinking-water system
Three-stage under-sink reverse osmosis treats water at a dedicated faucet. It complements—not replaces—whole-home softening. Actual reduction claims, output, and service needs depend on the exact installed model and water conditions.
One vessel or separate vessels?
Plus uses mixed resin/carbon in one treatment vessel, plus a separate brine tank and under-sink RO. Premium and Elite use dedicated softener and activated-carbon vessels, plus a brine tank. Elite also includes RO. The vessel layout should match space, water needs, sizing, and service requirements.