Alkalinity and pH - I am confused but happy

[jereece]

Thanks Richard.

Just as a follow-up, my swimmer load has always been just a couple family members, I don't use any kind of fountains, it has not rained in a month, I have not used Trichlor or Dichlor in years. I always take my readings in the late afternoon (shade). I do get a few leaves every now and then, but nothing abnormal.

Is it possible that the decrease in pH after I added borax was due to my new liner? As I stated in my original post, I put a new liner in this spring filled, with fresh water and added CYA to 25ppm. I know the CYA caused the initial pH drop, but after I added the borax could the liner (being plastic) have some kind of ion exchange going on that would cause the pH to decrease until a balance was reached? I used to work in a chemical treatment plant and know that ion exchange resin is made of plastic and even earth can have some ion exchange properties. I was just wondering if something from the liner could have caused this until it reached equilibrium.

Thanks again for your insight.

Jim

[chem geek]

I really don't know, but many chemicals exposed to new environments (i.e. water) will leach out especially initially before reaching more of an equilibrium. We know, of course, that plaster works that way, but that's a specific chemical process of curing. With vinyl, I'm sure it's not so dramatic, but something like that could be happening.

I would say that if many people with new vinyl pools find initial pH dropping or not rising as quickly and then later find it stable or rising faster, then you very well could be right. Otherwise, this is just one more mystery without an explanation.

Richard