Pool Stored?

[Shirker]

I went into my local pool store to pickup a bottle of polyquat for my upcoming closing. Just for giggles I brought them a sample of water to test. They want me to add more calcium to help protect the vinyl liner of my above ground pool. They claim that without enough calcium in the water, the calcium in the vinyl will be leached out causing it to become brittle and prone to cracking.

Do vinyl pool liners have some sort of calcium additive? Or are they just concerned with corrosive properties of soft water? My calcium is currently at 175. This isn't something I need to be concerned with, right?

They also warned me about buying powdered shock (which I don't use) from big box stores because they use stabilizer as a filler and claimed that theirs does not contain any CYA. I thought I was about to catch them until I read the label. They were selling calcium hypochlorite. So I at least feel good about that. With low calcium levels, I was going to try to calculate the cost of cal-hypo vs. the bleach I am currently using to see which is the most economical. If it works out, I might use the cal-hypo next season.

 

[Smykowski]

Partly pool stored. At least they told you the truth that their powder isn't stabilized with CYA (hopefully they qualified it with "But too much calcium is bad, too...." ).

My vinyl pool has a CH reading of 100. We have yet to hear of not enough calcium ruining liners. It's usually low pH that eats them up prematurely.

That said, as long as you do the math to figure out what's cheaper, and make sure you don't drive the CH too high (yes, vinyl liners can have scaling), there's nothing wrong with chloronating with CalHypo.

 

[SunnyOptimism]

Chemically speaking, there is NO calcium in vinyl. So adding calcium to a vinyl liner pool has nothing to do with the liner material. Typically you add calcium to a vinyl pool to harden the water against foaming. Ca ions interfere with the ability of water and organics to produce foams. To do this, you only need about 150ppm of CH.

Adding too much CH to a vinyl pool can potentially lead to scaling. Ca scale can be very rough and the sharp edges can lead to hurt feet or tears in the liner.

 

[chem geek]

See this post that explains that some vinyl liners contain fillers that have calcium carbonate, but that as long as the percentage of this is low then there is no problem, not only for not saturating with calcium carbonate, but also for resistance of issues from low pH.

 

[Shirker]

chem geek, thanks for the info.