Quote Originally Posted by waterbear View Post
One often overlooked reason for having calcium in a vinyl pool is to help prevent foaming. Soft water will have more of a tendency to foam than hard water. Personally, I think a calcium hardness of around 100-150 ppm would be more than enough. Might be in intersting experiment if anyone cares to do it! Other than that low calcium should not be an issue at all!
Well, my CH level is 50ppm this season, pretty low, but I haven't seen ANY evidence of foaming, ever. How low does it have to be before that can happen? Also, I'm a bear about keeping my chlorine levels stable, so that's probably preventing it as well.