Stabilizer Stain

[mretglobal]

I'm new to this forum seeking help to this question...

I've recently opened our inground vinyl lined pool for the season and had our maintanance person add Stabilizer that created a large whitish stain that has not gone away over the last 2 weeks. The product only contains cyanuric acid. Has anyone experienced anything remotely close to this and may be able to offer suggestions for it's removal or is this a liability issue with the product's manufacturer?

Thanks,

Mretglobal

[chem geek]

How was the stabilizer added? Was it just dumped in one place in the vinyl pool? If so, then it settled to the bottom. Cyanuric Acid dissolves very slowly. It is acidic so it is possible that where it landed at the bottom, the acidity damaged the vinyl (though normally it is chlorine that would cause a bleaching effect -- acidity usually just thins, breaks down or weakens the vinyl).

Cyanuric Acid is usually added slowly into the skimmer and caught in the filter to slowly dissolve. Alternatively, it is put into a sock or panty hose and hung over a return flow. It is not to be just dumped into the bulk pool water as it dissolves too slowly.

[mretglobal]

How was the stabilizer added? Was it just dumped in one place in the vinyl pool? If so, then it settled to the bottom. Cyanuric Acid dissolves very slowly. It is acidic so it is possible that where it landed at the bottom, the acidity damaged the vinyl (though normally it is chlorine that would cause a bleaching effect -- acidity usually just thins, breaks down or weakens the vinyl).

Cyanuric Acid is usually added slowly into the skimmer and caught in the filter to slowly dissolve. Alternatively, it is put into a sock or panty hose and hung over a return flow. It is not to be just dumped into the bulk pool water as it dissolves too slowly.

You are highly perceptive in your reply since a small portion was added to the skimmer while the rest was virtually dumped into the pool by the them as I watched . Absolutely right that an acid will cause this effect if proper precautions are not taken.

Now what?

[mretglobal]

How was the stabilizer added? Was it just dumped in one place in the vinyl pool? If so, then it settled to the bottom. Cyanuric Acid dissolves very slowly. It is acidic so it is possible that where it landed at the bottom, the acidity damaged the vinyl (though normally it is chlorine that would cause a bleaching effect -- acidity usually just thins, breaks down or weakens the vinyl).

Cyanuric Acid is usually added slowly into the skimmer and caught in the filter to slowly dissolve. Alternatively, it is put into a sock or panty hose and hung over a return flow. It is not to be just dumped into the bulk pool water as it dissolves too slowly.

You are highly perceptive in your reply since a small portion was added to the skimmer while the rest was virtually dumped into the pool by the them as I watched . Absolutely right that an acid will cause this effect if proper precautions are not taken.

Now what?

[mretglobal]

CAN CYANURIC ACID CREATE A WHITE STAIN ON A VINYL LINER WHEN ADDED DIRECTLY TO A POOL AND NOT THROUGH THE SKIMMER?

[AZMermaid]

CAN CYANURIC ACID CREATE A WHITE STAIN ON A VINYL LINER WHEN ADDED DIRECTLY TO A POOL AND NOT THROUGH THE SKIMMER?

If you have a colored liner, yes. It is an acid and as any concentrated, slow dissolving acid will do, it can start thinning the vinyl (as chemgeek explained) and the color on the vinyl is usually surface, and doesn't go completely through so it will look "bleached", or might have thinned the liner. I'd take a dive and check the liner.

[quantumchromodynamics]

The liability issue is with the person who put the stabilizer in incorrectly. Why was the stabilizer just dumped into the pool? What are the directions that are printed on the container that the stabilizer came in? How long did the stabilizer sit in one place? Are you 100% sure that it was stabilizer that was added? What other chemicals were added, and how, after the stabilizer was added?

[quantumchromodynamics]

Richard, do you think that if someone added liquid chlorine while the cyanuric acid was on the bottom, that the highly concentrated chlorine would be absorbed by the cyanuric and turn it into a product similar to Dichlor?

[chem geek]

Richard, do you think that if someone added liquid chlorine while the cyanuric acid was on the bottom, that the highly concentrated chlorine would be absorbed by the cyanuric and turn it into a product similar to Dichlor?

No, that's not how it would work. As the Cyanuric Acid (CYA) dissolves into the water, there is already chlorine in the water that will immediately combine with it (in less than a second). Most of the Free Chlorine (FC) is bound to CYA -- in a typical pool with an FC near 10% of the CYA level, around 97% of the chlorine is bound to CYA. This is far less reactive so would be unlikely to bleach the liner.

It's more likely that the acidity of the CYA affected the liner since it was physically on top of it and there's not much circulation to dilute and keep the pH in check directly under CYA. Or it's more likely that if someone added chlorinating liquid or bleach quickly in one place not over a return flow, that this denser liquid settled to the bottom causing fading (bleaching). Concentrated chemicals on a liner are a no-no, especially if they are either chlorine or acidic. A Trichlor puck is both so would be even worse.