Quote Originally Posted by iwannapool View Post
I've seen it said that a vinyl liner pool doesn't need calcium, makes sense. But I have also read if you have a heater and a vinyl liner then you need calcium.

Why does the addition of a heater require calcium?
Doesn't the heater put metal in contact with the water?
Does the lack of calcium cause the water to become corrosive?
Will this result in the heater failing prematurely?

If so, then that is why the manufacturers warranty requires it.