Vinyl liner stain

[johnau]

Hi all, over the winter my vinyl liner has gotten seriously stained. This has happened before, and citric acid cleans it up. So I put in citric acid about 2 weeks ago, and by the next day the stains were gone, so I happily went about my business.

Here is where things went awry.

Several days later I noticed a bunch of brown/green sediment on the bottom of the pool, I assumed it was algae, and so I brushed it and shocked the pool with bleach. And I did a water chemistry test and found the PH and TA were very low, so i put in 10 pounds of baking soda. I've since read that shocking and raising PH after using citric acid is problematic, but here we are. This turned the pool water a nuclear colored green/brown. But I had to leave out of town on business for a week, so I left it.

Now, the water is pretty clear, but the liner is completely stained again.

Here are my latest water chemistry results:

I know my CYA is too high, i have a sump pump on order so i can drain water and refill. I'm also planning on switching to SWG in the next month or so to avoid puck-related CYA problems.

pool capacity - 20,000 gallons
Water temp - 64
FC - 3.5
CC - 0
PH - 7.2
TA - 60
CYA > 100

I have available some Natural Chemistry Metal Free, Cu-Lator metal eliminator, Jacks Magic Magenta Stuff, polyquat 60, and more citric acid. I have not added any of this at this point.

So, can you advise of the proper procedure to get rid of these stains?

Thank you!

 

[YippeeSkippy]

Hi there Johnau, welcome to TFP.

It sounds as if you have iron in your water. Do you know where this is coming from? Are you using well water? Is this a brand new problem?
What all do you use chemically in your pool? You mention having done a citric acid treatment....right?

THe problem with the iron is that while it is "in solution" it can be handled thru use of a sequestrant. It is when it "falls out of solution" that you see it stain and look funky. The best solution is to get that iron out of there or just change out the water and re-fill with iron free water. One cool way to get it out of there without changing the water is to use Polyfil (the stuff they sell for crafts) and use it as a filter in the skimmer. Or live with it via using sequestrants (least preferred).

Read this--> Trouble Free Pool

My first bit of advice is to take a sample to the pool store and ask them to test for metals. DO NOT buy anything from them at this time, just the test please. Tell us what they find.

THen run over to CVS or Wallyworld and pick up some cheap Vitamin C tablets. Do the test as described in the above PoolSchool lesson. Let us know what happens.

Can you do that?

Maddie

 

[johnau]

Hi Maddie, thank you for replying.

Yes I’ve done the citric acid in previous years, and did it a week or 2 ago. I’m not positive where the iron is coming from.

But I do know citric acid gets rid of the stains, they just came back so I guess I need to use sequestrants or drain. I’ll also look at Polyfil for the filter to help. It’d be nice not to have to drain that much water.

I’ll go get a metal test done at the local pool store and post the results.

 

[johnau]

Hi, i just wanted to close the loop on this. since my CYA level was off the charts i needed to drain water anyway. so, i've drained a significant portion of the water, and the stains have disappeared and metal test shows very minimal levels now. thanks for your assistance on this.

 

[YippeeSkippy]

Hi there- Ok, I hope this drain & refill helps your problem.

Are you up on pool chemistry now? Do you have one of the recommended test kits to keep monitoring your pool yet? Have you got your SWG up yet?

Maddie