What Does High pH Really Mean?
Does your pool or spa water leave your skin irritated, feel chalky, or look cloudy? You may be dealing with high pH levels. While many owners focus on chlorine, pH balance is just as important for keeping your water clean, safe, and comfortable.
The pH scale measures how acidic or alkaline water is. The ideal range is 7.2 to 7.6. Once levels creep above 7.8—especially over 8.0—problems can quickly develop in both pools and spas.
High pH can:
- Irritate skin and eyes
- Reduce chlorine’s effectiveness
- Cause cloudy water
- Lead to scale buildup on surfaces and equipment
Let’s explore how to safely lower pH in your pool or spa, even if you’ve never worked with water chemistry before.
How to Lower pH in a Pool or Spa
If your pH reading is above 7.8, it’s time to act. The good news? The process is straightforward with the right tools and a step-by-step approach.
1. Test the Water First
Use a reliable test kit or test strips to confirm pH levels. If your reading is above the recommended 7.2–7.6 range, you’ll need to lower it to restore balance.
2. Choose the Right pH Decreaser
There are two common types of products used to lower pH levels:
- Dry Acid (Sodium Bisulfate) – Easy to measure and handle; ideal for both pools and spas.
- Liquid Acid (Muriatic or Hydrochloric Acid) – Highly effective but must be handled with care. Use gloves, goggles, and avoid using in enclosed spa areas unless well-ventilated.
Note for spas: Because spa volumes are much smaller, acid should be added in very small amounts—start with lower doses and adjust only as needed.
3. Add the Acid Safely
When applying acid:
- Always add acid to water, not the other way around, if pre-diluting.
- For pools: slowly pour acid directly into the deep end or near return jets while the pump is running.
- For spas: add small, measured doses and circulate the water for even distribution. Pre-diluting in a bucket of spa water is often recommended for better control and safety.
4. Circulate and Retest
Allow the system to circulate:
- For pools: run the pump for 4 to 6 hours, or overnight if possible, before retesting pH.
- For spas: circulate for at least 30–60 minutes, then test again. The smaller water volume causes pH levels to shift more quickly, so always retest before adjusting further.
If levels are still high, repeat the process gradually—overcorrecting can swing the pH too low.
What Causes High pH in Pools and Spas?
pH imbalances often develop slowly and can be easy to overlook—especially during heavy usage or hot weather.
Common causes include:
- Using liquid chlorine (sodium hypochlorite), which is alkaline
- High-alkalinity tap water used for topping up
- Frequent shocking or overuse of chemicals
- Poor circulation or filtration
- Aeration from fountains, jets, waterfalls, or excessive splashing
- Organic matter or algae growth from infrequent cleaning
Note: Algae don’t directly raise pH, but they thrive in poorly balanced water, often accompanying high pH levels.
How to Keep pH Levels Stable
Prevention is key especially in spas, where smaller water volumes mean faster chemical shifts.
Tips for Pools and Spas:
- Test 2–3 times a week during active use
- Balance total alkalinity first (optimal range: 80–120 ppm)
- Add chemicals in small, measured doses. Never guess
- Use algaecides or clarifiers when needed
- Maintain clean filters and ensure proper pump operation
- Cover your pool or spa when not in use to reduce evaporation and chemical drift
Final Thoughts
Whether you’re managing a backyard pool or a compact spa, keeping pH in check ensures:
- Less skin and eye irritation
- Clearer, cleaner water
- Longer equipment life
- More effective chlorine use
With just a bit of regular testing and small corrections, you can keep your water balanced, inviting, and easy to manage.
