Is it harmful to mix different kinds of salt in the softener?
Generally speaking, no; however, certain water softeners are designed for specific water softener products and may not function as well using alternative products. For example, use of rock salt in a cabinet model softener is not recommended because this type of softener is not easily cleaned and rock salt leaves a residue of insoluble matter. It can also bridge. Mixing of coarse and fine products (for example pellets and rock salt) is not recommended as bridging could also result from this practice. It is recommended that you allow your unit to go empty (or nearly empty) of one type of salt before adding another to avoid these problems.
