Why And When Should You Acid Wash Your Swimming Pool?

Published November 28, 2022

There are a variety of tasks that a swimming pool owner must do to maintain the cleanliness and safety of their pool. Skimming, vacuuming, and adding chlorine are a few examples of such tasks.

Among these, acid washing is perhaps the most overlooked routine.

While it’s understandable since it’s not something you’d do every week, one must still keep in mind that it’s an incredibly important part of pool maintenance. But what does acid wash mean, anyway?

What Does It Mean To Acid Wash Pool?

As the name implies, acid wash involves acids and washing. To be more specific, it’s when you mix hydrochloric acid with a lot of water, then spray the solution onto the pool’s surface.

Since it involves acid, it’s supposed to be an incredibly delicate routine.

After all, if you use too much acid, you might dissolve several layers of the surface. And if you use only a little, it may not lead to any improvement. But what should be the improvement? you may ask.

Why Acid Wash Pool?

The idea behind a pool acid wash is to use the hydrochloric acid’s corrosive properties to get rid of tough stains and other build-ups. However, there are other benefits to an acid wash.

Below are some examples of the improvements an acid wash can bring to your pool’s surface:

Eliminate Tough Stains

The first improvement would, of course, be the reduced amount of stains.

An acid wash doesn’t eliminate stains in general, but the particular tough stains that you cannot get rid of with vacuuming or regular brushing. These include stains from chlorine, dirt, and minerals.

Remove Sticky Algae

Algae is normally something you can take care of with some rough brushing, but that’s not always the case. If a particular patch of algae remains long enough, it can become incredibly sticky.

An acid wash is often the only solution to the problem in those cases.

Improve Pool’s Appearance

Certain pool owners may acid wash pool even if there aren’t any stains or algae.

Their main goal, in those cases, is to simply improve the pool’s appearance. And it’s likely because the outer layer of the surface has already faded or discolored. An acid wash can make it smoother.

So, as you can see, an acid wash is an essential part of pool maintenance, which may come as a surprise since it’s not discussed as often. Well, that’s because it’s not something you often do.

How Often Should You Acid Wash Your Pool?

A general rule of thumb is to acid wash a pool every five years. That’s why it’s not something pool owners talk about as often, at least when compared to other pool maintenance routines.

After all, brushing should be done twice per week, while adding chlorine must be done once a week.

Nevertheless, that doesn’t make acid washing any less important. But keep in mind that unlike brushing or skimming, there’s such a thing called ‘too often’ as far as acid washing is concerned.

Since an acid wash involves harsh chemicals, doing it more frequently than necessary can damage the pool’s surface. It’s also worth noting that certain pools don’t require an acid wash.

For one, you mustn’t acid wash above-ground and vinyl-lined pools.

Otherwise, you can damage the pool lining, negatively affecting its appearance and effectiveness. Acid washing, in general, is just a delicate process and must be handled with care.

With that in mind, the following section should guide you through the process.

A Step-By-Step Guide To Acid Washing

What You Need

• Pool brush
• Drainage hose
• Spray nozzle
• Safety equipment (acid-resistant gloves, boots, and mask)
• Protected clothes (long-sleeved shirt and long pants)
• Muriatic acid
• Watering can
• Two (2) garden hoses
• Soda ash
• Water test kit

1. Drain And Clean The Swimming Pool

Since muriatic acid is harsh, you’d want to use as little of it as possible.

If the pool’s surfaces have patches of algae and a bunch of dirt, you may be forced to use a lot of the acid. Hence, before you start, you must drain the pool, then clean it thoroughly.

Your main goal for this step is to get rid of the debris to reduce the amount of acid needed to eliminate tough stains. Just use whatever tool you have at your disposal with that goal in mind.

Examples of tools you can use include a pool brush, a hose, and a spray nozzle.

2. Replace The Hydrostatic Relief Valves

If you’re aware of the standard procedures to drain a pool, you likely know that it requires you to remove the hydrostatic relief valves. They prevent the acid from seeping into the groundwater.

Once the hydrostatic relief valves are gone, the pool water may flow out.

Since the ‘pool water’ you must deal with likely contains muriatic acid, you don’t want that to happen. So, before you proceed with the acid wash, you must reinstall or replace the hydrostatic relief valves.

3. Prepare The Solution

Usually, the acid mixture consists of equal parts of muriatic acid and water. However, you can play with the ratio, mostly by reducing the amount of acid, if you think the mixture will be too harsh.

The less acid you add, the gentler but less effective the mixture will be.

Place the mixture in your watering can.

4. Connect The Garden Hoses

Connect one end of the first garden hose to a spigot and put the other end to the pool. Don’t put a spray nozzle on this hose. Do the same with the other garden hose, but this time, put a nozzle.

Keep the water running on both.

5. Acid Wash Pool

Now, you can acid wash the pool. It’s mostly manual work since you have to move to the area you want to acid wash. Wet the surface with the hose without a nozzle before you pour the acid mixture.

Acid can damage dry surfaces, so wetting it first is a crucial step.

Upon pouring the mixture, use a brush to scrub the surface. Wait for around 30 to 60 seconds, depending on how dirty the surface is before you rinse it using the garden hose with a nozzle.

This is where it gets tricky since you have a hose on one hand and a watering can on the other. That’s why you need an extra person to hold the scrub and the hose with the nozzle spray.

Do this throughout the entire pool.

6. Neutralize The Acid Mixture

When acid washing, you mustn’t let the mixture linger on a surface for too long. That’s why as you work your way through the pool, you must add soda ash to the bowl where the acid mixture ends up.

You must continuously add soda ash to balance the pH level.

Two pounds of soda ash should be enough to neutralize one gallon of the acid mixture. You might have to read the manufacturer’s instructions and notes for both the soda ash and the muriatic acid.

7. Check The pH Level With A Test Kit