Use of RO will definitely take out iron and hardness (and everything else down to around 1-5% of the original concentration in the feedwater). One issue you might have with iron in chlorinated water source is that iron catylyzes oxydation of Thin film composite membranes so you will burn these if you have iron and CL2. Most of the home water RO's are probably cellulose acetate membranes (I never checked to see what this market uses), but even those membranes will get iron fouled and act with chlorine to "burn" holes in the membrane. Once that happens, you have raw water passage through the membranes and essentially have no reverse osmosis removal occurring.
Use of salt should be programamble on all softeners, even the low end timer based ones. Basically you get around 25Kgr. removal per cubic foot of resin regenerated at 12 lb. / ft3. All home softener units I ever saw are 1 ft3 size and use 8-12 lb. salt per regeneration. Set the timer to regenerate every 4300 gallons of water per 100 ppm hardness. In other words, if you have 200 ppm hardness, then regenerate every 2250 gallons. If the water analysis is reported in "grains per gallon" (old style reporting method) then multiply by 17.1 to convert to ppm as calcium carbonate hardness.
To remove hardness use a softener. To remove iron up to 3 ppm and hardness, use a softener. To remove iron above 3 ppm, add iron out to the salt or use the salt with an iron remover built in (or just add a couple of lbs of citric acid to the tank every now and then). To reduce all elements and reduce organics, use an RO. Keep in mind that household RO's have low overall recovery, so they waste approximately 50% of the feedwater as purge, They area water hog if your water costs are high. Softeners on the other hand have around 90-95% recovery.
Mike
