1. Confirm units
Hardness is often reported in mg/L as CaCO₃. Iron and manganese are typically mg/L. pH has no mg/L unit.
2. Separate aesthetic from health concerns
EPA secondary standards include aesthetic/nuisance guidance such as iron 0.3 mg/L, manganese 0.05 mg/L and pH 6.5–8.5. Those are not the same thing as primary health-based maximum contaminant levels.
3. Do not pick a treatment by symptom alone
Orange staining can suggest iron, but treatment depends on the form and concentration. Odor can have several causes. Private well users should confirm with appropriate testing.
4. Match treatment to certification and operating conditions
Once you know the target contaminant, compare certified reduction claims, influent limits, flow rate, pressure drop and maintenance.
Next step
Run your numbers through the Water System Planner, then verify any product against its actual service-flow, pressure-drop, capacity and certification data.