Copper sulfate, iron, and magnesium begin to leach out of this 30 year old plaster surface because of applied stain sequestering solution. 

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The white plaster surface is revealed even after years of staining.

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This is more than muriatic acid in a watering can.

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This spa has heavy copper staining as well as magnesium.

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Both spa and pool surfaces are sanded to restore the smooth plaster look and feel.

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