Dull Yellow discoloration of vinyl liner

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R

run53

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May 4, 2010
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Not sure if this is the right forum to post this.

Pool Numbers as of this morning (pool opened on Saturday, 5/2):

TC=5.5
FC=5.5
pH = 7.2
TA = 75
Calcium = 140
CYA = 15 (added 8 lbs of powder CYA but not retested yet)


Over the last couple of years I've been noticing a dull yellow is stain on the liner. It has very defined edges as you can see in the attached photo. The photo doesn't make it appear as bad, but it is actually worse in real life. Very noticeable.

It doesn't brush off or even scrub off so I doubt it's algae. It's also happening on a steel bench in the deep end and on/around my steel stairs. Seems to be mostly around where there is steel from either the walls. Is something happening behind the liners with the steel? Any ideas to diagnose what the problem is? It just keeps getting more pronounced every year. This is the 8th season I've had the liner.
 

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good question....I thought that myself, but I would lean towards no. This is happening in different areas of the pool with different sun exposures. Also, why would it be such a defined line? Just above that line gets the same sun and is not stained.
 
Test to see if they are iron stains. Crush up some vitamin C tablets, put them in a sock and hold the sock down on the stain for a couple of minutes.

If it is iron, you will see the spot disappear or diminish significantly
 
jblizzle said:
Does that happen to be the level you lower the water to during the winter? That would explain the defined line.
Click to expand...

Hmmmm.... interesting observation. I will measure it when I get home but I bet it's close to winter level.

But it's not like that all around the pool. Just in the area of the picture (wall area only) and on some of the steel stairs and bench. Also notice, it only goes down to where the steel wall ends and the deep end bowl begins. Must have something to do with the steel walls behind it.
 
jblizzle said:
Does that happen to be the level you lower the water to during the winter? That would explain the defined line.
Click to expand...

I think you nailed it. I went home last night and after careful inspection, it does look noticeable around the pool at that level. And yes, that is right about the winter water level.

Now the questions is why and is it possible to clear it?
 
duraleigh said:
Test to see if they are iron stains. Crush up some vitamin C tablets, put them in a sock and hold the sock down on the stain for a couple of minutes.

If it is iron, you will see the spot disappear or diminish significantly
Click to expand...

Finally got around to getting some vitamin C tabs. I simply rubbed it over a stained area and instantly, the stain is gone. Didn't even have to rub with any force or length of time. This is a stain that would not budge no matter how hard I scrubbed.

Now that I know that vitamin C solves it, how can I treat the whole pool. There is no way I can rub Vitamin C tabs as there is too much stained area, including some of the floor deep end.
 
What this means is you have metals in the water. Do you use well water for filling and does it have iron in it?
Might also be copper. Do you use copper based algaecides?

you can solve the stains with an Ascorbic Acid treatment. Acscorbic Acid is pretty much same as Citric Acid.
You can get a decent size container of AA powder for fairly inexpensive.

here is a link with instructions

Ascorbic Treatment to rid Pool of metal stains
 

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Divin Dave said:
What this means is you have metals in the water. Do you use well water for filling and does it have iron in it?
Might also be copper. Do you use copper based algaecides?

you can solve the stains with an Ascorbic Acid treatment. Acscorbic Acid is pretty much same as Citric Acid.
You can get a decent size container of AA powder for fairly inexpensive.

here is a link with instructions

Ascorbic Treatment to rid Pool of metal stains
Click to expand...

I do not have a well. I fill with municipal water. Also, I have never used algaecide. So I have no idea where the metals are coming from.

Thanks the link....I will try the AA treatment.
 
So, I've been doing lot's of reading about metal stain removal. I noticed that some folks have had success with Metal Magic alone (no AA). I looked at the instructions on MM and they don't say anything about lowering the FC like the AA treatment does. Just to make sure the pH is between 7.5-7.8. Since lowering my FC is scary (I am sure to get an algae bloom), I am thinking of trying the MM method first.

But first, i want to make sure I read correctly that MM treatment does not require FC reduced to 0 (or at all). Can anyone confirm? Also, I realize this will cloud the water, but how long before it will be swimmable after adding the MM?

Or should I just try the AA treatment from Pool School?
 
jblizzle said:
Ah ok.

Well we know the AA will work. But there are a few posts about the MM working as well.
I do not know enough about it to offer suggestions unfortunately.
Click to expand...

Yeah....you know after re-reading the AA method in pool school it doesn't look that bad. My only concern was how quickly I could get the FC back to about 4.0 since my CYA is at 70(SWG). Seem like I should be able to start adding bleach the day after the AA treatment. But it says to add chlorine slowly. What does this actually mean? like raise it 1ppm per day? Is that slow enough?

Seems like it would be best to pick a stretch of cloudy days to do this process to help avoid an algae bloom. I guess that's what the Poly 60 is for, but how long will that last?
 
You mentioned it's just where there is steel behind the liner. Could it be the stains are coming from rusted steel behind the liner?

I would think that if its from metals in the water the stains would be more evenly distributed; this is what happened in my pool. I successfully used the AA treatment to get rid of the stains and have used a sequestrant (Jack's Magic Purple Stuff) ever since to prevent them from returning.
 
Saturn94 said:
You mentioned it's just where there is steel behind the liner. Could it be the stains are coming from rusted steel behind the liner?

I would think that if its from metals in the water the stains would be more evenly distributed; this is what happened in my pool. I successfully used the AA treatment to get rid of the stains and have used a sequestrant (Jack's Magic Purple Stuff) ever since to prevent them from returning.
Click to expand...

well, the closer I look, I can see the yellowing even on the pool bottom where there is no metal. They do seem more pronounced where the steel steps and walls are though. Maybe it's just the way the sun hits the pool.
 
I battled the stains all summer last year and I've done the AA a few times. You will be amazed how your liner clears.. The AA seems to eat chlorine as soon as you add it back at first but it will begin to hold. I kept my Ph at 7.3 also. I kept my FC between min and max recommended levels. I use a sequestrant called metal Klear every 2 weeks. This year I "think" I finally have the stains under control and with splash outs and adding water. I have no idea how they got there in the first place. You can read my Metals post from last year.
 
Before I spend over $100 on products to remove the metal stains, please check my plan below that I summarized from pool school:

1) FC=0, pH = 7.2
2) add 1 quart Polyquat 60 to 24K gallon pool ($21)
3) add 1.5 - 2lbs. ascorbic acid ($30)
4) after stains are gone (hopefully 30 min) add Metal Magic 2.5 quarts($48)
5) leave filter running until water clear again (hopefully 2-3 days)
6) re-balance water after 24 hours to bring up TA and pH (not to exceed 7.2)
7) after balanced, start raising FC slowly so as to not raise pH above 7.2 (no shocking) - what does slowly mean????
8) If stains re-appear, check pH and add more MM if needed
9) apply weekly maintenance dose of MM
 

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