Swimming Pool Blog

Acid Burned Pool Plaster

Pictures of Pitted Pool Plaster
by Rob Cox August 08, 2014

Pictures of Pitted Pool Plaster

Acid washing a plaster pool is necessary when returning a pool to normal operation, after years of neglect.

An acid wash is a purposeful stripping of a thin layer of plaster, to expose the fresh, unstained plaster beneath.

When pool plaster is very stained - it's necessary to use a lot of acid, and a lot of elbow grease to remove the stains, often requiring pouring the roughly 50% diluted acid on the walls several times.

When acid is poured on plaster, it immediately goes to work, bubbling and gassing, in a hideous dark yellow color. The fumes are strong, breathing and protective gear is necessary to prevent breathing in the mist or getting it in your eyes.


Here's the main point of today's post. If you are ever going to acid wash your pool, protect your plaster by avoiding these Acid Washing Pitfalls: 

  • Acid left for longer than 30 seconds before rinsing can etch the plaster more than you want.
  • Acid can burn the center of the floor, from acid draining from the shallow end to the deep end.
  • Acid left sitting in the bowl of the pool can wear the plaster thin around the main drains.

And, here are pictures to prove it!

The solution to this problem? Use a grinder to smooth it out - partially. But it's best avoided in the first place. Pool plaster is only about half an inch thick.

To avoid burning your plaster, creating rough spots - try this instead: 

  • Rinse the surfaces with water before pouring an acid mix
  • Rinse acid washed walls quickly, within 30-45 seconds. Rinse horizontal surfaces several times.
  • Use a push broom or hose to constantly disturb the river of acid running down the center of the pool floor.
  • Pour the bowl first, then neutralize the waste water with 2 lbs of soda ash for every gallon of acid used.


- Rob