Calcium???

[BrandonM7]

I know this is a three year old post, but it seemed like a good one to pick back up in regards to this --

What about the steps? What are the steps made of in a vinyl IG pool? I ask this because of the consideration given to fiberglass pools and potential gelcoat leaching. I have some bubbling and cracking of the face of 6 year old steps in my vinyl IG SW pool. I've kept the water well within acceptable levels the entire 6 years - not a single slip, honestly. And I keep it open and balanced year round. I know the levels I maintain have never gone out of whack (pH, TA, FC, cya) I have never maintained CH due to info from poolsolutions back when I started. Now my steps are bubbling and they won't cover warranty because my CH is 46ppm. I don't know that it caused the problem, but it's an easy out for them because I haven't kept it up. My bad there - should have kept it up for warranty alone. I'm wondering if I should go ahead and bump it up just in case that caused it - I figure having 100ppm isn't going to hurt anything anyway, and if it protects the steps from further damage that would be cool. I'd just like to know if it's responsible for the damage.

[waterbear]

I have never found any evidence that low calcium can damage the gelcoat in any way except for either higher incidence of staining or the formation of 'black spotting' or "cobalt spotting' which is actually cobalt crystallizing out of the gelcoat (gelcoat does contain colbalt). This look like little grey to black spot on the surface that start out pinhead size and grow into a 'crystal' that is raised from the surface. Newer gelcoat formulation are supposed to be more resistant to their formation.

I have seen firsthand that higher CH levels do help limit iron staining.

[PJM361]

I know this is old but, I figured it would be good to add to this info. My situation is vinyl liner over concrete walls with SWCG. I know that calcium is not a concern but, I have Cambridge pavers for my coping and even though I have an auto cover closed except when swimming or cleaning I'm getting white effervesces on the underside of the coping that hangs over the pool. How many PPM should I have in my water to stop this? Right now it's at 30-40PPM pool is 1 year old. Thanks in advance for all the help.

[PJM361]

Talked to a guy at the pool store and he thinks the white stuff on the coping is from the salt and not from the lack of calcium, does that sound right?

[waterbear]

Does it dissolve readily when wet? If so it is salt. IF not it is either calcium scale or the dreaded silica scale which is much harder to remove.

[PoolDoc]

You can test for calcium carbonate scale using a drop of muriatic acid. If it's calcium carbonate (like limestone or marble in plaster), it will fizz, from released carbon dioxide.