You guys are gonna love this...

[CarlD]

Greg,
Please explain to me how water without calcium is corrosive, but water with calcium is not.

I understand how high salt levels can be corrosive, how non-neutral pH can be be corrosive and how too much chlorine can be corrosive.

I also understand how a leechable chemical that is present in one environment, like the calcium in concrete or plaster pools will be dissolved by water that lacks calcium. Therefore calcium in the water presents a saturation to prevent it dissolving from the concrete or plaster.

But please explain to me how the vinyl will be damaged by low calcium if the other chemicals in the water are balanced? Exactly what elements react with the vinyl and how does the calcium prevent it?

Oh, and I keep my water VERY light on calcium and have YET to require a pump seal.

Oh, and by the way, I'm moving this thread to the China Shop.