Pool Liner Stained From Acidity Too High

by Clare
(Narromine NSW AUstralia)

I have been running our pool with too much acid. It's has stained the liner and plastic components of the pool a brown colour, especially at the water line.

What can I use to fix it now that I have the pH balanced?

Thanks for the question Clare

There are basically three kinds of stains:

Biological (algae, pollen)

Chemical (acid, chlorine)

Organic (grass clipping, leaves)

In your case the question mentioned running the acid too high which will lower both your alkalinity and pH.

Swimming Pool Supplies

For a brown chemical stain like yours, the best solution would be to use granular ascorbic acid. Add 1 lb. of granular ascorbic acid per 10,000 gallons of pool water. I think in Australia you use the metric system so that would be about 0.45kg or 453 grams.

Mix the ascorbic acid in a bucket of water. Slowly pour mixture around the perimeter of the pool. Turn on the pool filter for 8 - 10 hours. Recheck the pool liner to see if the stains have disappeared. Add a metal sequestering chemical, such as Metal Gone, if stains are still visible. Pour 1 qt. of liquid Metal Gone per 15,000 gallons of water directly into the pool.

Turn on the filter for another 8 hours or until the stains have disappeared. It might be necessary to increase the pH after stain treatment. If you have this problem in the future there's an easy way to determine if the stain is mineral or organic.

Fill two white socks, one with chlorine the other with ascorbic acid. Put one of each sock on the stain and check in 3 - 4 hours. If the chlorine starts to lighten the stain, you will know it's an organic stain. If the ascorbic acid works, it's a mineral stain. This eliminates any guessing.

Hope this helps and have a wonderful Summer


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