Do I Need to Acid Wash My Pool?

Maintenance Issues

• Maintenance issues related to concrete swimming pool basins and their waterproof plaster topcoats typically involve problems with rough surfaces as well as staining. Swimming pool chemicals act on concrete pool plaster topcoats gradually, roughening and sometimes staining their surfaces. Rough concrete pool plaster topcoats are uncomfortable to a swimmer's skin, unfortunately. Staining caused by pool chemicals also develops on a concrete pool's plaster topcoat, and even stubborn embedded algae contamination. Fortunately, pool plaster topcoats can be restored to their former luster and smoothness.

Acid Washing

• Acid washing of a concrete swimming pool's plaster topcoat is called for whenever the topcoat's surface is just too abrasive on swimmer skin. Also, pool plaster topcoats that resist manual scrubbing of stains often benefit from an acid washing treatment. Lastly, concrete pool plaster topcoats can develop a problem with pool algae, which will embed itself in the topcoat's surface. Acid washing a concrete swimming pool's plaster topcoat eliminates algae when chemical disinfection and manual scrubbing isn't working.

Process

• In order to acid wash a swimming pool's plaster topcoat the pool has to first be drained. While draining a concrete swimming pool prior to acid washing, all pool surfaces are manually scrubbed as the pool's water recedes. A 50/50 solution of pool acid and water is used to lift a thin layer of the plaster topcoat through manual scrubbing with an acid brush. Acid wash residue left in a concrete swimming pool is typically neutralized with soda ash before it's drained away.

Considerations

• Never acid wash vinyl liner or fiberglass swimming pools. Acid washing of a concrete swimming pool's plaster topcoat is also known as a "drain and clean." The general rule of thumb is that if you can no longer see the bottom or your concrete swimming pool's floor, acid washing is necessary. At the time of publication, it costs about $600 to have a concrete swimming pool's plaster topcoat professionally acid washed.