There are only one or two softeners that have any filtration properties for more than chunks or rather large pieces of anything. They “tout” a 20 micron filter ability and a compartment for the addition of a “filter mineral”. All other softeners, unless using a “mixed bed” configuration (which is uncommon) have next to no filtering ability. Further more, the softener will fail if “dirt” gets into it in any substantial amount. A sand filter or other turbidity type filter on the other hand will have a filtration rating of somewhere around .5 to 50 micron (the smaller the number the smaller the particle, .5 mic. filters bacteria). We can see particles down to about 45 microns. A softener can only filter with the distributor tube “basket cone” which is designed to keep the resin (about 1/16″ to 1/32″ in dia. (very large as far as micron size)) in the mineral tank and out of the plumbing system. And when a softener goes into the backwash cycle the resin would be “flushed” out of the tank to drain before “dirt” would be. The only exception would be with the use of a “top basket” cone, otherwise the drain line flow (gpm) will empty the tank of all resin. I am talking ‘downflow’ as opposed to ‘upflow’ service, same principal in reverse. Resin is very light in weight and when the bed is “fluidized” in backwash etc. it will exit the tank very easily (thus the need for 50% “free board” (empty space) except in those one or two makes that ‘vacuum pack’ the resin bed and hold it captive (immovable). The slots in the “cones” are measured in thousandths of an inch, correct me if I’m wrong but microns are measured in millionths of an inch.
To ‘filter’ chemicals and metals they must be ad or ab sorbed, with the exception of specific resin (nitrate, lead etc.) filter cartridges. This resin is not cation (for hardness etc. removal) but anion (lead, nitrate etc.) and is specific to those parameters. Drinking water filtration is a very separate issue from ion exchange softening of water.
The amount of sodium added from ion exchange softening is 7.8 mg/l for each grain per gallon softened. To get any extra sodium the person has to ingest the water, if they ingest a liter with an original 10 gpg hardness they receive 78 mg of sodium. Only folks with a sodium restricted diet need to be concerned and if they are they know how to adjust their intake with the foods
they consume.
Far too many people gauge their water quality with the following statement; “it tastes good, no smell and there’s nothing floating in it”, this is sad. Any water contamination problem that can cause serious health problems can harm without giving a taste, smell or visible indication of being present; they are totally undiscoverable without testing.
Another item is water source; residential well or “municipal supply” using wells, surface or a combination of same. These are extremely important differences, and totally different waters, they must be kept separate in discussion of potential problems and more importantly, treatment.