Washing your pool with acid is very useful, whether your pool looks like a swamp, or if you just want it to look clean and fresh. Pools need this process, also called "draining and cleaning," when winterizing them is not done properly, or when a lot of algae is formed from long-term lack of use or maintenance. Acid washing essentially wears down the top layer of cement leaving a fresh layer, so doing it often is not recommended. But once in a while, it's a great idea!
Steps

Step 1. Completely drain your pool
As you drain it be sure to clean up any debris. Once it is completely empty, begin the acid washing process.

Step 2. Put on the protective equipment that includes clothing, glasses, mask, gloves and boots

Step 3. Mix 1 gallon (3
8 liters) of acid with one gallon (3.8 liters) of water in a shower. The acid has to be added to the water and not the other way around.

Step 4. Wet one of the walls with a hose
The hose must not have a sprinkler and the faucet must be open at all times.

Step 5. Pour the acid mixture onto the wall from top to bottom in 10-foot (300 cm) sections at a time, allowing the acid to work on the wall for about 30 seconds
During this time, you have to scrub the wall with a brush.

Step 6. Rinse the section you just washed quickly and thoroughly
Before moving on to the next section, be sure to thoroughly rinse the wall so the acid doesn't continue to wear down the cement.

Step 7. When you have finished the acid wash, neutralize the pool
The washing process leaves a foamy puddle of residue on the bottom that you have to remove before it damages the floor.
- Apply soda ash to the puddle of debris and scrub the mixture with a pool brush. You will need to use 2 lbs. (0.9 kg) of sodium carbonate for every gallon (3.8 liters) of acid.
- Pump the mixture into a container using a submersible pump.
- Throw away what you pumped out, as the acid can kill frogs, fish, and plants. Rinse the container.
- Pour water over any remaining residue, carefully rinsing around the drain.
Advice
- If you do not see results after the first attempt, you will have to proportionally increase the amounts of water and acid, scrub harder or let the acid act on the wall for longer. The process may need to be repeated a couple of times to get the walls clean.
- If acid gets into your eyes or mouth, rinse with the hose (no spray) for 15 minutes. If it does contact your skin, rinse for 30 seconds as soon as possible after contact.
Warnings
- If you don't rinse the acid off well, it will continue to wear down the cement. Don't let the acid go from the shallow side to the deeper side of the pool, as it will wear down the pool floor on its way.
- When using acid work carefully. Wear protective clothing, transport the acid safely by securing it to the vehicle, rinse after you've finished acid washing the pool, and work with at least one other person.
- The acid wash technique should never be used on a vinyl pool. Detergents and conditioners are better for these pools.