Stained vinyl liner

[Joshsaw]

Hey guys-new to the site, but have been referencing it for about a month to straighten out my pool. I have owned a 30k gal vinyl liner for 3 years and have yet to really dial it in. This is admittedly mainly my fault, as I have been a lazy pool owner, but I am turning over a new leaf. Now have a Taylor test kit, am trying to follow BBB, and putting the time into maintenance. Here is my issue: early in the season, my CH bottomed out to 40ppm, Cya was over 100. I was testing through a local pool store, and they made their recommendations to balance, but did not stress the dangers of low CH or issues with high CYA. Long story short-I have a vinyl liner that appears to have metal staining. I did try the pool stores metal stain removal process in the summer, to no avail. I have since turned my back on them and am attempting the fix myself, but could use some advice. Through the use of BBB and the pool calculator, my info is as stands: FC=0.2ppm CC=1.0 pH=7.5 TA=100 CH=190. I have been adding 8% bleach at levels recommended by pool calculator and have driven CC down from as high as 4.4, with FC regularly falling back to 0. Water looks good, but I need to straighten out FC/CC and get rid of the liner stain.
Now the question...should I superchlorinate as recommended in the Taylor handbook, should I SLAM as recommended here, or try to rid myself of the (maybe) metal stains? Help!

 

[257WbyMag]

Welcome to TFP!

You have several issues. First of all, if your CYA is 100 or more, you need to change out water to lower that value to somewhere between 30 and 50 ppm. It's tough to SLAM your pool with a CYA that high. Because you have a liner pool, you will need to change out water in stages to avoid liner problems. Once your CYA is down, you can SLAM the pool more efficiently.

As for the stain, there are ways to tell what the source of the stain is. If you are suspecting metals as being the source of the stain, you can test for this by applying a vitamin C tablet to the stain for a few minutes. If it lightens, it's metal and we can point you to the process needed to deal with it. If it doesn't lighten with the vitamin C, then it is likely organic and proper chlorination will solve the issue.

By the way, what test kit are you using to get your test results?

 

[Joshsaw]

Thanks for the fast reply. My test kit is Taylor k-2006 fas-dpd. I was wondering if the cya might be a source of my frustration, as it seems that I am not getting the results I expected in terms of getting my FC right. If I follow through with adjusting cya by draining and makeup water, then achieving proper chlorination, would an organic stain clear up on its own?

 

[Smykowski]

If I follow through with adjusting cya by draining and makeup water, then achieving proper chlorination, would an organic stain clear up on its own?

If the stain is organic, and if you complete the SLAM process conpletely and correctly, and if you then maintain the proper FC/CYA ratio, then yes.

Even though the water looks ok, it sounds like you have something in the water consuming your chlorine.

 

[Joshsaw]

Ok- I haven't drained before, but used the waste port on my filter to drain as much as I could (no bottom main drain) and setup two siphon hoses off top foot of surface. After a couple of hours, I added a hose to the deep end for makeup, leaving siphons in place. I then Let that go for a few more hours, then pulled the siphons. I am now filling back with two hoses. I will retest cya levels after running pump a couple hours from finish of fill. I am curious to see how much the cya will drop in this process. Also, how much water can safely be drained without putting too much strain on a vinyl liner? Thanks- I will be touch with results.

 

[linen]

Welcome to tfp, Joshsaw

Also, how much water can safely be drained without putting too much strain on a vinyl liner?

As long as you don't have a high ground water level, you should be able to drain until there is still 12" in the shallow end.

 

[Joshsaw]

Finished a partial drain and refill-cya is reading 65. I know this is still high, but it took a lot of h20 to get to this point. Should I try again, or go ahead and start to chlorinate? I may not have time to drain again until next weekend. It looks like about 6-7 gal of 8% bleach to shock to 19 ppm. Time for something other than a pool...

 

[linen]

How much sun does you pool get during swim season?

 

[Leebo]

Do you plan on closing the pool for the "winter"??

 

[Isaac-1]

One more thing, Do you know if your fill water is high in metals? And why do you suspect metal staining? If the fill water is the source of the metals you may have a long term battle to keep them sequestered, however if it is due to addition of pool chemicals which contained copper or other metals you may only need one time treatment to remove them.

Ike

 

[Joshsaw]

Pool is in full sun for probably 8 hours in season. I will close the pool probably in a month or so. We don't have a cover, so cleanliness in spring has been an issue. I used a stain I'd kit from jack's majic earlier in summer and it removed the stain with the component listed for metal-also removed some of the color from the liner. Was wondering if I should partial drain over winter to handle CYA.

Sidebar-after makeup water yesterday, wanted to chlorinate after work today since FC is essentially zero. Added 7 gal of 8% bleach in an attempt to reach 19ppm shock level. I didn't have time to properly follow slam technique because I was chasing my 3 year old around. Tested the pool about 3 hours after adding the chlorine and FC was 1 ppm, combined chlorine increased to 3.2ppm from 1.0 yesterday, ph 7.2, TA 90 ppm, and CH 170 ppm- again with a CYA of 65.

Can I assume that even though I can't seem to reach a stable FC level, that I at least temporarily shocked enough to clean up some of the water?

 

[Joshsaw]

Little more history on stain- you all are dredging up pool memories I was trying to forget! Opening pool last spring, we had an algae outbreak. Used pool store recommendations to clean up, which included aglaecides. At this time, pool was out of balance with ph below 7, cya over 100, and ch only around 40. Pool store was very casual about the numbers, and to be honest I didn't know any better. Looking back is like a slap in the head. Attempted to balance levels after treating for algae. I assume the shifting of pH may have precipitated something on the liner. The pool store tested and found no metals actually in the water. Went through their recommended $150 metal stain treatment with no luck. I suppose I have a hope that if I can achieve proper chlorination, it may turn out to be organic and clear up.

 

[Leebo]

If you can lower CYA down just a touch more to 50 you'd save yourself a TON of chlorine. You can however SLAM a pool with 65ppm CYA.....it will just take a higher dose of chlorine. I wouldn't lower it lower than 50 as you're closing soon anyways. Hope the CYA drops over the winter some.

Any chance you can post a photo of the water....the stains.....and some test results??

 

[Joshsaw]

I will try to get a pick up soon-what other test results would be helpful?

 

[Leebo]

PH
TA
FC
CC
CYA

Let's start with these to dial in a plan to SLAM before winter.

 

[Joshsaw]

Ok- here is a photo of the shallow end with staining on liner where return is located.
Last test results
Ph 7.2. (Down from 7.6 before makeup water)
TA 90
Ch 170 (down from 190 before makeup water)
Cya 65
FC 1.0 (after "shock" with 7 gal 8% bleach trying to get to 19 ppm)
CC 3.4 (up from 1.0 ppm before shock)

Any advice at this point is appreciated. I will not have time to follow through with a slam until weekend. Thanks to everyone.

 

[Joshsaw]

I think I scared everyone away with the pic of the mystery stain...am I right in hearing that my life will be that much easier if we drain enough to take cya to 50. Slam and regular chlorination should then be more manageable, thus off setting water costs. Then, once chlorination is set, deal with staining. What are recommendations for stain I D? Vitamin C test...any others? Thanks.

 

[Leebo]

Whoops.....sorry about that. Just got back from vacation and am still running around like crazy.

Vinyl liners are VERY hard to stain. Odds are very much in your favor that it's simply organic in nature. Your test results show that you've got a mess on your hands and how you don't have a green pool is beyond me. Preforming the SLAM process should be your first step. Now if you chose to drain to lower the CYA level first, or SLAM at higher CYA levels is up to you. You're right there on the verge of it really being a call that has no real right answer.

 

[Melt In The Sun]

I'm not sure I would worry about lowering it more...you could, but it may not be worth the water cost (~6000gal) for the amount of bleach you'd save.

A SLAM will require attention and regular chlorine dosing regardless of the CYA level....that is the most important part.

The vitamin C test will ID iron stains, and rubbing a trichlor puck on the spot will ID organic stains. Like you said, you can worry about that once the SLAM is done. If your stains are organic, you will likely lighten them in the SLAM process.

 

[Joshsaw]

Thanks for the guidance. I will probably slam ASAP. Question: since I am close to winter closing, would cya drop naturally during winter?