We have a water treatment for both softened or hard water. This is a very special blend for all steel boilers. It has a special blended secret additive as well, so please dont ask. Remember that most water softeners will leak around 2 to 3 ppm hardness on the outlet with out polishing. Our product contains a chelating and sequestering agents, a specific buffering agent, organic passivating agent, oxygen scavenger, alkalinity booster, non polymeric dispersing agents (polymers get too jumpy in applications like this where feed control, etc can be all over the map). The hard water treatment obviously has the addition of a hardness complexing agent. You must specify if you have copper tubes as this product is blended for all steel boilers. You use about a Teaspoon for an 1 1/2" to 3 3/4" scale engine for a four hour run. It is $25.00 for approximately a pound container plus S & H and tax when applicable.
You should do a quarterly internal inspection and wash out as well. Do not use an acid based water treatment on your boiler, the outcome is not going to be good. If your boiler water ph is below 8.5 when you fire up you will cause what is known as acid wasting of your boiler metal. Only use a reliable vendor for any water treatment who can advise, test and support the treatment they offer.
Boiler Magic Water Treatment for Live Steam