from $650 to $800 (for SPA add $150)
Also called a drain & clean, an acid wash becomes necessary if the pool has turned into the "black lagoon". This may occur if the winterizing process is not done properly, or if the pool has been stagnant for a period of time so that algae has taken over (usually when the pool is opened late in the summer the algae had a chance to thrive in the warm weather). If you notice scaly, man-phibian creatures splashing around out back, it's probably time to drain & clean.
Our general rule of thumb for determining the need for an acid wash is: if you can see the bottom of the pool (the floor) then you can bring it back with chemicals, labor, and filtering. If the floor is not visible, the cost of the chemicals and labor will generally be greater than the acid wash charge and take much, much longer. Also, extensive algae blooms will stain plastered pools, making an acid wash desirable.
An acid wash is, put simply, purposeful stripping of a tiny layer of plaster, exposing fresh plaster beneath. Therefore, it is ill-advised to make it an annual custom, which will accelerate the need for re-plastering. Most plaster coats (sometimes called whitecoat or marcite) are in excess of 1/2", so a few careful acid washes should not hurt.
You may also decide on an acid wash, not because of swampy conditions, but just to bring out a brighter, whiter finish. Mineral stains and/or deposits, chlorine stains, even dirt stains.. .an acid wash is always a dramatic aesthetic improvement.