What's the deal with calcium hardness ?

[mcrofutt]

How important is it to maintain proper calcium hardness in a tub ?

[Pathfinder]

Short version- Not enough hardness in your water will cause excessive foaming but more importantly can be corrosive to your heater element.

Too much hardness can cause cloudy water and mineral deposits can form on your tub surface and can build up on your equipment and your heater element.

So it is important to keep good levels.

[Jacuzzi Jim]

 Some say yes some say no,I say yes, but not the level most suggest which is between 250 and 450 ppm I like to see it around 200 or so.