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Acid Wash Pool: How, When and More

Acid Wash Pool: How, When and More
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When you have a pool, the last thing you want to happen is for it to get dirty. No one wants to swim in murky water, and if you’re paying someone else to clean your pool, this can also be an expensive problem.

That’s why having the right information on acid washing a pool can save both time and money! In this post, we will discuss how to do so effectively and safely.

What Is Acid Washing and What Does An Acid Wash Do For a Pool?

The definition of acid washing your swimming pool is to use acid to dissolve or neutralize the metal ions in your pool. This can help remove stains from hard water, algae growth, and other contaminants that may need to be removed for a clean, fresh look on your pool surface.

Acid washing is used where chlorine can’t handle any more contaminants such as hard water build-up (from calcium) stains and algae growth. It helps dissolve those types of issues down into a harmless liquid so that they won’t end up harming swimmers.

Is It Safe to Acid Wash a Pool?

Acid washing is safe for your pool, but it’s important to take precautions when adding an acid or other chemicals to it. Keep children, pets, and other swimmers away from the area during treatment – especially if there is a strong smell of chemical fumes in the air.

How Much Does It Cost to Acid Wash Pool?

Acid washing a pool at home can cost as little as $25-$50 for materials. Professional acid washes of swimming pools will most likely be more expensive, but the cost should depend on how large your pool is and what type of stain removal you need to be done. Depending on these factors, you can expect the cost to range anywhere from $150-$300 for a professional job.

Should You Acid Wash Your Swimming Pool?

You should only acid wash your swimming pool when necessary. This is because the acid can be dangerous to you and your family if it isn’t neutralized after use.

However, you should definitely acid wash your pool when you notice stains, hard water, and algae growth that is hard to remove with regular maintenance.

What Kinds of Pools Can Be Acid Washed?

Different kinds of pools can be acid washed, such as in-ground pools, above-ground pools, and even small spas.

Above Ground Pools: You generally don’t need to acid wash an above-ground pool unless it has a vinyl liner or metal surface that can be dissolved with the acid.

In-Ground Pool: For in-ground pools, you should only consider using this method if there is a concrete and metal surface.

Small Spas: Small spas should only be acid washed if there is no other way to remove algae growth without causing major damage to the pool’s liner or tile work.

Pros and Cons of Acid Wash Pool


  • Removes stains and algae – Acid washing removes hard water, stain streaks, dirt, bugs, and other organisms.
  • Prevents future staining or algae growth – If you acid wash your pool routinely, it will prevent smelly bacteria accumulation. This bacteria can cause a green film to accumulate on the surface, making it look dirty even when it’s clean. The best part is that this occurs without any scrubbing or physical contact with chlorine, so there’s no danger from chemical burns if you touch something in the process.


  • A pool could be rendered unusable – If you acid wash your pool too much, then the surface will become rough and brittle. This is especially true if there’s a high ratio of muriatic acid to water that can happen on accident or when someone uses the wrong type of hose!
  • It takes time – Acid washing doesn’t just take an hour. It can take several hours for all traces of chlorine to dissipate before refilling with fresh water, vacuuming debris from pools’ surfaces, and changing filters.
  • Regular acid wash does not kill bacteria – They’ll eventually accumulate over time but at least without any abrasive chemicals being used by mistake!

What Type of Algae and Stains Will Acid Washing Remove?

There are a few types of algae and stains that acid washing will remove.

Magnesium Stains: These stains are caused by a high pH level in the pool or when there is not enough calcium and magnesium, which can happen if your water softener isn’t working properly.

Tannin Stains: Tannins come from leaves that have been deposited on top of an improperly maintained surface. This type of algae will become rough and brittle over time without treatment.

Calcium Hardness Stains: These stains occur due to scale build-up around the pipe screens. They’re also known as “hard water” spots because they worsen with hard water usage vs. softened waters’. However, acid washing won’t remove these types of stains unless combined with brushing before refilling with fresh filtered water. Even then, it might take more than one.

Copper Stains: These stains are usually caused by a copper pipe connected to the pool. They can also be due to green algae that thrive in chlorine-rich water.

Iron Stains: These are typically rusty stains on surfaces. They’re generally found near metal pipes or fittings, often with an orange tinge.

Oyster Shell Calcium Carbonate Stain: This type is most commonly seen when someone tries adding calcium carbonate directly into their pool without first adjusting the pH levels.

Hard Water: These types of stains are usually caused by high mineral content in the water, with a milky white or cloudy clarity.

Algae Growth: Algae are often brownish green and can cover surfaces of your pool.

Why Do You Need a Pool Maintenance Professional for Acid Washing?

You should always consult a pool maintenance professional before acid washing your pool because it can be dangerous. A pool maintenance professional can help you understand the safety precautions, tools needed, and step-by-step instructions for acid washing your pool.

For example, a pool maintenance professional will know how to properly acid wash your pool or spa and the right time for you to do it. They’ll also ensure that all safety precautions are in place before any work begins, so there’s no risk of injury due to improper use of chemicals. This way, everyone stays safe while enjoying their backyard oasis!

When to Acid Wash Your Pool

The best time of year to have an acid wash done on your pool is in the spring or fall because it’s not too hot out. This way, you don’t need to worry about any chemicals being heated up by the sun, which can be dangerous if splashed into the eyes, nose, or mouth. Also, this will help stop algae growth during hotter months when pools are under more stress from high temperatures and overwatering.

A good rule of thumb is to look into acid washing your pool if you see:

  • Stains
  • Algae
  • Stagnation
  • Repairs
  • Wear and Tear

How Often to Acid Wash Your Pool

Pools should be acid washed when they have stains that won’t go away. They also need to be washed every year before opening after winter due to harsh winter conditions on pools. It’s important to keep them clear and clean.

You should acid wash your pool when you start noticing the above signs of a build-up or if there is no other way to remove them without damaging the pool liner. Regular brushing can help prevent these unwanted chemicals from building up in your swimming pool. You can expect to acid wash your pool every six months, depending on these factors.

However, you may want to consult with an expert about whether you’re ready for this type of treatment. Pools should not be acid washed if they are close to being opened – the chemicals involved might harm swimmers.

How to Acid Wash a Pool

Items Needed to Acid Wash a Pool

Here are the items that you need to acid wash your pool in a bulleted format.

  • A pool pump and filter system with at least 300 gallons per minute capacity or higher.
  • An acid wash solution consisting of 50% muriatic acid, 40% sodium bisulfate [sic] (or soda ash), and an optional 30% hydrochloric acid. This is a dilution ratio that usually works well for most pools. The total amount needed will depend on the size of your pool.
  • A bucket to mix up the solution, stirring stick if you have one available; goggles; rubber gloves; long sleeves shirt or jacket that covers wrists/elbows while chemically handling gear; safety shoes such as steel toes work boots or other protective footwear such as Gortex both are highly recommended when working.
  • You will also need your pool vacuum cleaner with a leaf bag attachment, brush or long-handled scrubbing pad for the steps to remove stains (if desired), and extra filter media.

Step 1: Drain the Pool

To properly acid wash your pool, the first step will be to drain the pool water that is currently in place. If you have never drained the pool before, make sure that you understand all that is involved in this process.

If you are not careful about where the pool water drains, you could have an empty pool and a flooded yard. Pool owners should first read up on the best way to drain their swimming pool before starting this process.

Step 2: Personal Protective Equipment

Let’s face it, working with acid can be scary. You must make sure that when doing pool acid washing, you are protecting yourself as best as possible. We highly recommend using something like goggles, masks, gloves, and boots. Make sure that the products you are using are going to stand up against the acid wash process.

Step 3: Combine Acid and Water

You are going to combine acid and water so that you can start your acid washing process. There is a very important safety tip related to this part of the process. You will want to make sure that your water is in place before you add the acid to it.

When creating the acid mixture, you cannot put acid into the water; it must be done the other way around. Remember to wear protective clothing even when doing the mixing part of the project. Acid fumes are very strong and are dangerous to be around.

Step 4: Start on One Wall

Now you will start to acid wash the pool. The best thing to do is to get one wall of your pool completely wet. You can leave this hose that you use running and allow it to keep a thin layer of water on the wall at all times.

We strongly suggest having a pool care expert handle this process if you are at all uncomfortable with any of these steps. While the water is running on the wall of the pool, you will pour your acid mixture starting from the top and letting it drain towards the bottom.

It’s best to create your acid mixture in a watering can as it makes it easier to apply to the pool. Again, ensure you also have your protective gear on at this time. The acid wash is going to flow down to the pool floor, and you will be exposed.

Step 5: Scrubbing and Cleaning

While the acid wash is spreading down the wall of the pool, you should be using an acid brush and scrubbing any pool stains or remaining residue that you see on the pool walls. This process must happen quickly because you don’t let acid sit on the pool walls for all that long.

Step 6: Rinsing the Acid Wash

After the acid wash has sat on the pool wall for about 30 seconds, you need to use your garden hose to start rinsing it off. If you do not rinse water on the wall fast enough, the plaster will start to deteriorate, and it is very bad for the walls of your pool.

This is why it makes sense to work in sections while you are doing this. Ensure that each section is handled with care.

Step 7: Neutralize the Pool

When you have finished cleaning all of the pool walls and pool stains, you will be left with a puddle of acid wash and water at the bottom of your pool. You will need to neutralize this acid puddle so that it does not cause any damage. The best way to do this is to use soda ash.

Acid Washing Safety

Acid washing your pool can be dangerous if you don’t handle the chemicals properly. Check out the following acid-washing safety tips.

  1. Wear the appropriate kind of clothes, mask, safety goggles, and gloves.
  2. Handle the chemicals carefully to avoid acid splashes and spills on yourself and others, especially not on a windy day. But, if you get it in your eyes, rinse immediately for 15 to 20 minutes with water from the tap, a wet toilet, fresh lemon juice, or vinegar. See your doctor if the pain persists!
  3. Keep your pets and children out of the area where you are acid washing.
  4. Keep your pool deck (if applicable) clear.
  5. Follow all instructions carefully in the right order and have a wastewater disposal plan. If you rush the job, you could make a dangerous mistake!
  6. Refrain from acid washing your pool on a windy day to avoid

The Bottom Line

As you can see, acid washing your pool is not as difficult or expensive of a process as it may seem. With the right information and tools now at your disposal, there’s no reason to let algae or stains build up in your swimming space any longer! Try it out for yourself or hire a professional with safety precautions in mind, and we’re certain that you’ll be thrilled with the clean water and aesthetic of your swimming pool.