We have been running a well for the last 3 years (1st time well water) no sulfer but there is iron so we have a softener that has taken care of the iron. We use a 20 micron cartridge which turns brown/orange due to the iron. I have never seen any sediment on the cartridge in the 3 years only the iron "growing" in the cartridge. So do I really need to use a 20 micron or can I switch to a 10. I think with a 20 and the iron it is clogging the cartridge prematurely. The softener does a great job maybe too soft but I don't want any minerals getting to my on demand water heater. Any thoughts? The filter is after the pressure tank and before the softener.