So a Merlin Vinyl liner rep told me that vinyl liners don't tolerate FC above 5 for prolonged time and that the vinyl can become almost sponge like thereby allowing water to get behind the liner. Seriously? FC of 5? For a SWG pool the range (non SLAM) is 4-6, per TFP. Why do I ask this? Because we have some sagging of the liner by the skimmer and side steps mid pool. I live on a hill and its been dry as the Sahara since July here so I don't feel like we have ground water behind the liner, but what do I know. Is there any legitimacy in what the Merlin rep says about vinyl liners and them becoming sponge like due to chemistry? Incidentally, this pool has not been perfect but it hasn't been way off either. FC is high right now because I'm coming out of a SLAM. FC is sitting at 14; TA = 150; CYA = 80, pH = 7.2. The liner is only just at 4 years old,. If I have to replace my liner, do any of you have recommendations?
Vinyl Liners and FC ranges
- Thread starter ajup2it
- Start date
Your CYA should buffer your FC. As long as you are in range for both the vinyl liner should be fine. Water behind the liner near the skimmer sounds more like a gasket problem or a crack in the skimmer.
The pool company and Merlin rep are saying that the vinyl is absorbing the water? Is this even a thing? It just seems strange to me. They claim there are no leaks in the gasket/skimmer box. 
No, it is not even a thing. The pool company and Merlin rep are blowing smoke trying to get rid of you. A pic of the sagging might help but I can promise you that chlorine does not cause vinyl to become spongy or "absorb water". That is simply absurd.
That's what I thought. This is the info they sent me:
Research by both chemical suppliers and vinyl manufacturers have confirmed that wrinkles in swimming pool liners develop because of the growth of the liner’s dimensions due to an excess of absorbed water. Technical articles published in the past have stressed the adverse affect of low pH as the main cause of liner growth. However, recent experiments have shown that high levels of sanitizers, whether bromine or chlorine, are the primary cause behind excessive water absorption. If the sanitizer level is allowed to remain high, double, triple, or even four/five times the normal amount of water can be absorbed. Therefore, controlling sanitizer levels is the number one priority when maintaining proper water chemistry, which is essential, if wrinkling problems are to be avoided. pH and cyanuric acid stabilizer levels are important secondary factors because they control the activity of the sanitizer. However, once wrinkles have developed, correction of pH or stabilizer content will not reverse the amount of water absorbed into the liner. In some cases, draining the pool and allowing the water to slowly desorb and evaporate has reduced or eliminated wrinkles. This procedure is not without risk because some liners, depending on age, may over shrink and not stretch back into place without failing. It has also been shown that once the surface of the liner has been affected by the sanitizer, water can rapidly reabsorb and the wrinkles may quickly reappear. Pool water clarity is often reduced by undissolved particulate matter introduced by bather load. Often these particles can be flocculated by the use of a clarifier and removed by filtration. The filtration system must be operated at it’s optimum level, since sanitizer alone cannot eliminate excessive particulate matter present in the pool, and the overuse of chlorine or bromine to improve clarity will increase the probability of wrinkle development.
Experiment Results:
1. Samples taken from heavily wrinkled liners, preserved in pool water, surface dried, weighed, then desiccated to constant weight, indicate that absorbed water can reach as high as 10% of liner weight. 2. Immersion testing of precisely weighed liner samples in pure distilled water and sanitizer free tap water showed that weight gain due to absorbed water levelled off at 0.6%. No dimensional changes occurred. 3. 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. 4. Immersion testing in water containing mono potassium persulphate type non-chlorine shock showed weight gains levelling off at about 0.6%, essentially identical to unsanitized tap water. 5. Samples from heavily bleached, used pool liners showed high weight gains in immersion tests in comparison to unbleached samples, taken from the same liner from above the waterline. Bleached test samples curled into tight coils with the bleached surface facing to the outside, as a result of greater water absorption occurring on the faded side than on the unfaded side.
Recommendations:
1. Do not allow free chlorine levels to exceed a maximum of 3 ppm, bromine levels a maximum of 4 ppm for long periods. Peak chlorine levels of 5 -10 ppm are required for superchlorination, but should be allowed return to the 2 -3 ppm range by natural dissipation. If bleaching of the blue liner colour is occurring, it is a direct indication that the chlorine levels have been too high. 2. Routinely stabilize outdoor and indoor chlorinated swimming pools with cyanuric acid stabilizer and maintain a minimum level of 50 ppm. It is recommended that levels be checked every 3 or 4 weeks. 3. Maintain pH levels in the 7.2 - 7.8 range. 4. Test result accuracy can be adversely affected by poor quality test kits and reagents. Keep reagents current by replacing them every 6 months and use a professional quality test kit recommended by your pool dealer. 5. Use non-chlorine shock to reduce organic contaminants, rather than high levels of chlorine or bromine during the pool season, as well as preparing the pool for winter. 6. Use flocculants and a filtration system in proper operational condition to remove undissolved particulate matter instead of high levels of chlorine/bromine oxidizer, to attain sparkling clear pool water. 7. It is important to maintain thorough circulation of the pool water in order to prevent settling and concentration build-up of chemicals on the pool bottom. Even liquid chlorine can settle to the bottom if sufficient inter-mixing is not achieved. 8. Frequent reports have been received concerning wrinkle development on walls of pools employing automatic pool covers. The phenomenon is most likely a result of chlorine concentration build up due to the air tight nature of the cover design and/or temperature differentials between water side and ground side of liner causing accumulation of moisture from condensation that forms ripples.
Research by both chemical suppliers and vinyl manufacturers have confirmed that wrinkles in swimming pool liners develop because of the growth of the liner’s dimensions due to an excess of absorbed water. Technical articles published in the past have stressed the adverse affect of low pH as the main cause of liner growth. However, recent experiments have shown that high levels of sanitizers, whether bromine or chlorine, are the primary cause behind excessive water absorption. If the sanitizer level is allowed to remain high, double, triple, or even four/five times the normal amount of water can be absorbed. Therefore, controlling sanitizer levels is the number one priority when maintaining proper water chemistry, which is essential, if wrinkling problems are to be avoided. pH and cyanuric acid stabilizer levels are important secondary factors because they control the activity of the sanitizer. However, once wrinkles have developed, correction of pH or stabilizer content will not reverse the amount of water absorbed into the liner. In some cases, draining the pool and allowing the water to slowly desorb and evaporate has reduced or eliminated wrinkles. This procedure is not without risk because some liners, depending on age, may over shrink and not stretch back into place without failing. It has also been shown that once the surface of the liner has been affected by the sanitizer, water can rapidly reabsorb and the wrinkles may quickly reappear. Pool water clarity is often reduced by undissolved particulate matter introduced by bather load. Often these particles can be flocculated by the use of a clarifier and removed by filtration. The filtration system must be operated at it’s optimum level, since sanitizer alone cannot eliminate excessive particulate matter present in the pool, and the overuse of chlorine or bromine to improve clarity will increase the probability of wrinkle development.
Experiment Results:
1. Samples taken from heavily wrinkled liners, preserved in pool water, surface dried, weighed, then desiccated to constant weight, indicate that absorbed water can reach as high as 10% of liner weight. 2. Immersion testing of precisely weighed liner samples in pure distilled water and sanitizer free tap water showed that weight gain due to absorbed water levelled off at 0.6%. No dimensional changes occurred. 3. 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. 4. Immersion testing in water containing mono potassium persulphate type non-chlorine shock showed weight gains levelling off at about 0.6%, essentially identical to unsanitized tap water. 5. Samples from heavily bleached, used pool liners showed high weight gains in immersion tests in comparison to unbleached samples, taken from the same liner from above the waterline. Bleached test samples curled into tight coils with the bleached surface facing to the outside, as a result of greater water absorption occurring on the faded side than on the unfaded side.
Recommendations:
1. Do not allow free chlorine levels to exceed a maximum of 3 ppm, bromine levels a maximum of 4 ppm for long periods. Peak chlorine levels of 5 -10 ppm are required for superchlorination, but should be allowed return to the 2 -3 ppm range by natural dissipation. If bleaching of the blue liner colour is occurring, it is a direct indication that the chlorine levels have been too high. 2. Routinely stabilize outdoor and indoor chlorinated swimming pools with cyanuric acid stabilizer and maintain a minimum level of 50 ppm. It is recommended that levels be checked every 3 or 4 weeks. 3. Maintain pH levels in the 7.2 - 7.8 range. 4. Test result accuracy can be adversely affected by poor quality test kits and reagents. Keep reagents current by replacing them every 6 months and use a professional quality test kit recommended by your pool dealer. 5. Use non-chlorine shock to reduce organic contaminants, rather than high levels of chlorine or bromine during the pool season, as well as preparing the pool for winter. 6. Use flocculants and a filtration system in proper operational condition to remove undissolved particulate matter instead of high levels of chlorine/bromine oxidizer, to attain sparkling clear pool water. 7. It is important to maintain thorough circulation of the pool water in order to prevent settling and concentration build-up of chemicals on the pool bottom. Even liquid chlorine can settle to the bottom if sufficient inter-mixing is not achieved. 8. Frequent reports have been received concerning wrinkle development on walls of pools employing automatic pool covers. The phenomenon is most likely a result of chlorine concentration build up due to the air tight nature of the cover design and/or temperature differentials between water side and ground side of liner causing accumulation of moisture from condensation that forms ripples.
Our SWCG vinyl pool is kept at about 3 - 3.5ppm FC and it is always clear and no issues with algae, etc.
Would you ask them to name the source for this "research". I would like to read more about this
This is very interesting. I only say this becasue I have been following TFP methods for a little over a year now, and my water has looked chrystal clear (yes you can read heads or tail on a quarter in the deep end.) During this time I have added nothing to the water except MA, and once my TA dropped to 70, I have added maybe 10oz in the last month. So very little of that. However, I do notice that my liner (2.5 years old) has faded a bit below the water line. I don't think anyone would notice on a picture, and most don't notice it all. However, no doubt it is starting to fade. Here is how I manage my pool:
I keep a CYA level of 50, and even though I have a SWG I keep my FC level in the 6-8 range, which is the recommended amount for a non SWG pool. I figured that chlorine is chlorine whether or not from a SWG or liquid bleach, and I would rather keep my FC in the higher range to keep algae away. The reason I have done this is that reading through the forum, it seems that a lot of algae problems start by owners trying to keep their FC at or close to the minumim and for some reason the FC drops below the minumum and bang...the algae starts. I havd not had to slam since I started using TFP and keeping my FC in this range. I have had no trouble maintining that with my SWG as I run my pump 24/7. I keep my SWG at 25% during the peak summer months (sometimes I have to turn it off if my FC drifts too high, I usually check daily) and now in the fall can keep it at 13% and maintain my FC levels. I also check my PH daily and it is always in the 7.5-7.8 range. So I know the PH is not affecting the liner. So I have a couple of questions, and would love to hear from other owners and experts here.
Vinly liner owners, have you noticed your vinyl liner fading keeping you FC levels in the recommended TFP range? Is is normal for a 2.5 year old vinyl liner to show some fading? The recommendations from the Merlin people say to keep your FC no higher than 3ppm while mainting a CYA level of at least 50. At TFP, we know this leads to algae problems. I would imagine some fading is normal, but I am more concerned about the integrity and wear and tear of the liner. The article mentions water absorption. Is this possible?
Do the higher chlorine levels have a different affect on vinyl liners, versus plaster or fiberglass? Is there less of an affect from higher FC levels on fiberglass or plaster?
I have read most of the science behind the CYA/FC chart and do not pretend to understand it. However, my take is that most of it relates to safety of swimming, the feel of the water, eye irritation, chloring smell, etc. I can attest to the fact that my water irritates neither skin nor eyes, feels great and has no chlorine smell. So my small sample of anecdotal evidence supports this. However, does this same science apply to the fading of vinyl liners or is it possible the water is safe to swim in but the higher FC levels will affect the vinly liner? We swim for very little time in water that is exposed to the vinly liner 24/7.
I am close to closing the pool this year, so next year I am going to try to maintain my pool closer to the SWG guidlines, which calls for lower FC levels. But man, that algae outbreak scares me! Thanks TFP and looking forward to hearing from everyone and any comments or suggestions about how I am managing my pool are always appreciated.
I keep a CYA level of 50, and even though I have a SWG I keep my FC level in the 6-8 range, which is the recommended amount for a non SWG pool. I figured that chlorine is chlorine whether or not from a SWG or liquid bleach, and I would rather keep my FC in the higher range to keep algae away. The reason I have done this is that reading through the forum, it seems that a lot of algae problems start by owners trying to keep their FC at or close to the minumim and for some reason the FC drops below the minumum and bang...the algae starts. I havd not had to slam since I started using TFP and keeping my FC in this range. I have had no trouble maintining that with my SWG as I run my pump 24/7. I keep my SWG at 25% during the peak summer months (sometimes I have to turn it off if my FC drifts too high, I usually check daily) and now in the fall can keep it at 13% and maintain my FC levels. I also check my PH daily and it is always in the 7.5-7.8 range. So I know the PH is not affecting the liner. So I have a couple of questions, and would love to hear from other owners and experts here.
Vinly liner owners, have you noticed your vinyl liner fading keeping you FC levels in the recommended TFP range? Is is normal for a 2.5 year old vinyl liner to show some fading? The recommendations from the Merlin people say to keep your FC no higher than 3ppm while mainting a CYA level of at least 50. At TFP, we know this leads to algae problems. I would imagine some fading is normal, but I am more concerned about the integrity and wear and tear of the liner. The article mentions water absorption. Is this possible?
Do the higher chlorine levels have a different affect on vinyl liners, versus plaster or fiberglass? Is there less of an affect from higher FC levels on fiberglass or plaster?
I have read most of the science behind the CYA/FC chart and do not pretend to understand it. However, my take is that most of it relates to safety of swimming, the feel of the water, eye irritation, chloring smell, etc. I can attest to the fact that my water irritates neither skin nor eyes, feels great and has no chlorine smell. So my small sample of anecdotal evidence supports this. However, does this same science apply to the fading of vinyl liners or is it possible the water is safe to swim in but the higher FC levels will affect the vinly liner? We swim for very little time in water that is exposed to the vinly liner 24/7.
I am close to closing the pool this year, so next year I am going to try to maintain my pool closer to the SWG guidlines, which calls for lower FC levels. But man, that algae outbreak scares me! Thanks TFP and looking forward to hearing from everyone and any comments or suggestions about how I am managing my pool are always appreciated.
It is a given that chlorine can fade the print from a vinyl liner. Just how much chlorine it takes to do that or how long it is exposed to chlorine is not at all known.
Years ago, I cut some liner strips and put them in jars inside the house at CYA 50 and 15 ppm chlorine, CYA 20 and 15 PPM chlorine and (as a sort of elementary control) FC 50 ppm and ZERO CYA. After 10 days, I could see absolutely no difference in ANY of the samples.....including the one with no CYA.
Leebo did a similar experiment and if I remember, very similar results.
In my opinion, this VERY unscientific experiment lead me to believe I had a liner where all the right stuff was done to prevent or minimize fading. Are all liners made like that? I have no idea, but it makes sense to me that some fade and some don't.
So, can chlorine fade a vinyl liner?.......I sure think so. How much chlorine and for how long is required?........I doubt anyone has any idea.
Years ago, I cut some liner strips and put them in jars inside the house at CYA 50 and 15 ppm chlorine, CYA 20 and 15 PPM chlorine and (as a sort of elementary control) FC 50 ppm and ZERO CYA. After 10 days, I could see absolutely no difference in ANY of the samples.....including the one with no CYA.
Leebo did a similar experiment and if I remember, very similar results.
In my opinion, this VERY unscientific experiment lead me to believe I had a liner where all the right stuff was done to prevent or minimize fading. Are all liners made like that? I have no idea, but it makes sense to me that some fade and some don't.
So, can chlorine fade a vinyl liner?.......I sure think so. How much chlorine and for how long is required?........I doubt anyone has any idea.
So if my pool chemistry hasn't been off the chart and my liner is sagging at the skimmer and steps, I wonder if pool water temp would do this? Last month it got into the 100's air temp and the pool was at 97 easily. I tried to cool it down but that was a real struggle. I'll post photos presently....so you can see what I'm talking about.
temperature wouldn't do it either. Is it sagging or wrinkled? How long has this been happening?
Here's the photos....it just started this summer. The bottom is fine, its just the wall by the skimmer. Interestingly the portion that is out of the water is more bulgy rather than flat like the other side.
Attachments
I did find some fairly interesting information in the link you provided, but the sagging of a water-logged, chlorine saturated water is nowhere to be found in the technical bulletins found at that site.
In fact, that site attributes the PRIMARY cuase of liner wrinkling to be low pH and many of us at TFP agree with that.
In fact, that site attributes the PRIMARY cuase of liner wrinkling to be low pH and many of us at TFP agree with that.
Thanks for the pics but they are not demonstrative enough for me to see what is happening......let's let others look at them....perhaps get a better perspective.
Anything to this?
After reading through the material again, they talk about "bleaching" not "fading." Duraleigh, I believe you are correct, a normal amount of fading is going to occurr regardless. I thought about doing the experiment you mentioned, but I do not have any of my liner left over.
The article seems to regurgitate much of what the pool industry recommends in somewhat technical terms. The only interesting thing is that they do recommend 50ppm CYA, but then recommend only 3ppm FC which would be a problem if one listened to that. Then they go on about using flocculents to clear up your water. Sounds just like what a pool store would recommend.
ajup2it, not sure I can help with what is causing the wrinkling, but I do not think it is your chemistry or my guess would be it would be all over or at least at the bottom of the pool and not just limited to the skimmer and the steps. Is it possible that since it is near the skimmer and the steps, where the PB makes cuts, that it is an installation issue?
Certainly the ink is going to fade over time, that’s a given.
Vinyl liners do not like excessive heat, yes they will stretch, that’s common sense.
Vinyl liners sucking in water? LOL
Vinyl liners do not like excessive heat, yes they will stretch, that’s common sense.
Vinyl liners sucking in water? LOL
So low pH being lower than 7.2? I've never struggled with low pH, only high pH unless I'm looking at this wrong. Generally my pH hovers around 7.8, historically.