If you’ve researched how to clean a pool, you’ve probably run across acid washing. The question is when should you acid wash your pool.
First things first, you shouldn’t have to acid wash regularly. This is more of an ultra-deep clean.
However, most pools will need an acid wash occasionally. It’s important to know why this type of wash is needed and when it needs to be done.
What Is An Acid Wash?
This is typically a task best left to the professionals. As the name implies, you’re using a type of acid to clean your pool. If you’re not extremely careful, you can burn your skin and eyes. If you do do it yourself, have someone with you in case something goes wrong.
When you acid wash your pool, you empty it out and use caustic chemicals to deep clean the pool. This removes old stains and stubborn algae. The chemicals cut through the grime in ways that standard cleaning just can’t.
The reason you don’t want to do it too often is you strip away a very thin layer of plaster each time, revealing clean plaster underneath.
Acid washing involves muriatic acid — a highly caustic chemical that can cause severe burns to skin and eyes, and produces dangerous fumes. Always wear full protective equipment including acid-resistant gloves, safety goggles, a respirator mask, and long sleeves. Never attempt this alone, and keep a garden hose running nearby to rinse any accidental contact immediately.
Why Acid Wash Your Pool?
Even with the best pool maintenance, stains build up over time. And, if it hasn’t been properly maintained, algae and stains build up even faster.
Usually, you want to acid wash your pool if it becomes nearly impossible to clean it any other way. When general cleaning isn’t doing anything to remove the stains from your plaster and the water always seems to be murky, this is a sign that algae are building up too fast for routine cleaning to keep up.
Signs You Need To Acid Wash
A little murky water and some light staining don’t mean you need to acid wash your pool. However, the following signs may indicate it’s time:
Expanding or deepening stains indicate buildup that has penetrated beyond what surface cleaning can reach.
When brushing, vacuuming, and chemical treatments no longer make a visible difference, an acid wash may be needed.
If algae returns within days of a thorough cleaning, it may have embedded in the plaster pores beyond the reach of normal treatment.
Persistent cloudiness despite proper filtration and chemistry suggests deep-seated contamination in the plaster surface.
If clarity fades within a day or two of a major cleaning, the plaster itself is likely the source of the problem.
A persistent gray, yellow, or green tint to the plaster means staining has gone deeper than surface-level products can address.
If you’ve recently bought a new home with a pool, you may choose to acid wash the pool to get a fresh start, especially if it doesn’t look too clean. The same is true if you haven’t used or clean in your pool in a while.
When Should You Acid Wash Your Pool?
While there isn’t a set rule for acid washing, it’s recommended to not do it annually. This will wear out your plaster quickly, leading you to need to replaster your pool.
Recommendations vary from every two years, especially if you live in areas with hard water, to every five years. With regular pool maintenance, you should be able to go for more than two years between acid washes.
Ideally, you should wait until spring or fall. You want moderate temperatures to better protect your pool liner during the acid wash process.
Plaster Age
Older plaster (7+ years) is thinner and more fragile. An acid wash on aging plaster may cause more harm than good — consult a professional to assess whether replastering is the better option.
Best Timing
Schedule acid washing during spring or fall when temperatures are moderate. Extreme heat causes the acid to evaporate too quickly, while cold temperatures slow the process and affect results.
Frequency Limits
Never acid wash more than once every 2–3 years — and every 5 years is better. Each wash removes a thin plaster layer. Too many washes mean an early $6,000–$15,000 replastering job.
Safety Requirements
Acid-resistant gloves, goggles, respirator, long sleeves, and a partner are all mandatory. Muriatic acid produces toxic fumes and causes severe chemical burns on contact.
Other Considerations
As your pool ages, the plaster may start to show signs of wear and tear. Flaking, holes and any signs of damage mean you probably shouldn’t acid wash your pool. The chemicals can accelerate the damage. For older pools, it may be best to replaster the pool completely since the current plaster may not be able to withstand the acid wash.
Also, if you’ve acid washed your pool within the last year or two and it’s showing signs of needing it again, contact a professional cleaning service. They can check your pool to see what’s causing the issues. They’ll also recommend things to do to prevent murky water and staining so you can avoid frequent acid washing.
Finally, ensure you have protective equipment on hand if you try this yourself. Also, take your time and be cautious.
Need a Professional Acid Wash?
Acid washing is one job best left to the pros. Koko Head Pool Service handles acid washing safely and correctly, protecting both your plaster and your health. Serving East Honolulu since 1995.
Call 808-399-4388Need help with regular pool maintenance? Contact us today to learn how we can help give your weekends back and ensure you don’t need an acid wash more often than absolutely necessary.
Image: irakli kharshiladze