A 9X54 tank would be very odd. Could it be a 10x54 which is common? What is you water usage like? What is the .19 iron ferric or ferrous? Ferric iron of .19 is very little vs ferrous. I would suggest getting the ph up first before trying to remove the iron. Rebuilding your 5600 would be minor cost and last quite awhile. I think calcite/corosex would be fine. I have used it in the past.
How old is the resin? What type of valve does it have? Softeners will not remove ferrous iron. If you are dealing with .19 ferric iron, use a softener and be done.