How can I 'harden' our water supply?
I want to be able to harden our water supply 'on demand' so that the CaCO3 total hardness level goes from around 60 to about 140 to trial the impact on cold brew coffee brewing.
Much simpler to mix at brewing time. Make 340 ppm CaCO3 water stock. Mix equal quantities of this with the 60 ppm water to get 140 ppm water.
My apologies. There was an arithmetic error.
That should be 220 ppm. 340 will give a hardness of 200 ppm when mixed in equal quantities with 60 ppm water.