Can I use ordinary salt in a Twin tec water softener that takes block salt?
The water softener will work with the granulated salt you are considering, but the increased surface area of the salt means more salt will dissolve than is necessary. The excess brine will be flushed out with the regeneration cycle and increase your use of salt to keep the brine tank charged, thereby nullifying your reasoning that the granulated or rock salt is cheaper than the salt blocks. It was designed for salt blocks – use salt blocks.
