pH and liner bubbles

[nagrath]

Take a look at this blog post: http://blog.ingroundliners.com/?p=321
Pictures look stunningly similar to mine.
I am having the liner replaced this fall. Here is what I have decided to do: 1. maintain my chlorine at 3ppm, no higher except during superchlorination.
2. maintain my pH as high as possible in the "normal" range, or about 7.5-7.8 3. Keep my pool cover open as much as possible (thus making it somewhat pointless, but enabling, I hope, my ability to keep the pH high enough). 4. Keep pool temperature no higher than 80 degrees. I think this will keep my liner from wrinkling. I am curious, however, as to why this information is not provided unless one looks for it very specifically. Other than reading that a low pH can cause wrinkling, I have seen no information about chlorine levels, temperature, and automatic covers as contributing to wrinkling in the general literature. The cover companies sure don't mention ANYTHING about how use of a cover can effect pool chemistry. I have to say the whole experience has left me disgusted and rather frustrated about the level of micro-monitoring I have to do to maintian my pool not in a swimmable state--that is easy--but in a state where I can be comfortable I won't have to relpace the liner every few years.

John

 

[UnderWaterVanya]

Take a look at this blog post: http://blog.ingroundliners.com/?p=321
Pictures look stunningly similar to mine.
I am having the liner replaced this fall. Here is what I have decided to do: 1. maintain my chlorine at 3ppm, no higher except during superchlorination.
2. maintain my pH as high as possible in the "normal" range, or about 7.5-7.8 3. Keep my pool cover open as much as possible (thus making it somewhat pointless, but enabling, I hope, my ability to keep the pH high enough). 4. Keep pool temperature no higher than 80 degrees. I think this will keep my liner from wrinkling. I am curious, however, as to why this information is not provided unless one looks for it very specifically. Other than reading that a low pH can cause wrinkling, I have seen no information about chlorine levels, temperature, and automatic covers as contributing to wrinkling in the general literature. The cover companies sure don't mention ANYTHING about how use of a cover can effect pool chemistry. I have to say the whole experience has left me disgusted and rather frustrated about the level of micro-monitoring I have to do to maintian my pool not in a swimmable state--that is easy--but in a state where I can be comfortable I won't have to relpace the liner every few years.

John

Wrinkled liner does not equal must replace... at least for me. Keeping the temp down isn't going to be easy depending on where you live and the 3ppm limit will make you maintain a low CYA 20-30? - causing more frequent monitoring to avoid dropping below minimum or the use of an SWCG and slightly lower than recommended CYA.

I'm not sure that anywhere in this research they looked at CYA and I'm not clear what type of Chlorine they mean when they spec the 3ppm - is that FC, CC, or TC? Is it measuring the active chlorine or just the FC generically - Chem Geek probably can shed some light on this.

I'd like to hear from liner pool owners that have used BBB at higher than 3ppm and hear what they have experienced generally. My liner was already wrinkled - no idea how the pool was maintained but the CH is higher than rational for my fill water so I suspect calhypo was used frequently. The liner is also faded in a couple of places leading me to think some trichlor powder or calhypo was dumped in without properly disolving it as well. BBB and a FC level of 5-13 plus a shocking process twice this year have not made any of the problems in the liner worse.

 

[Swampwoman]

Interesting article. However, scientifically they didn't really prove the case/cause for 10% stretch with this test:

Immersion testing of precisely weighed liner samples in chlorinated and brominated water in the 20 to 50 ppm range showed weight gains that continued to climb indefinitely and did not level off. Dimensional increases of 1.0 - 3.0% were also measured on these samples.

So they climbed indefinitely but did not exceed 3%? Something doesn't add up here. Where's the other 7 percent of the wrinkle coming from? (Acid, I am willing to bet )

I hope you resolve your issue, though I'm not certain that avoiding shocking will in fact prevent future problems. I am thinking if that were the only significant variable, there'd be MANY of us who have wrinkles...yet we don't.

My suggestion would be to seriously reconsider installing an under-drain sump with a line to the pump/filter when you replace the liner, and have it set up so that you can close all the other lines and pump out groundwater any time you get more than 4-6" rain for a few days. I have a hunch things might smooth out in this case.

My liner was exposed to foreclosure swamp debris and very low acid conditions for 1.5 years before we purchased the home. It is a 12-year-old liner. I had to superchlorinate to unbelievable proportions/durations, AND I had to clear ammonia this spring on opening. We now use bbb and maintain chlorine in the 4-6 range for our CYA, frequently dosing to 7.5 to maintain while at work on a sunny day. And I don't have but a few wrinkles from all that (touch wood .

But I DO have extensive drainage methodologies, including the sump tied to pump, a perimeter drain and two french drains that are graded down the slope of the property.