Muriatic Acid for Pools: What It Is, When to Use It, and Safe Handling Tips (In-Store Only)
Summary: Muriatic acid (hydrochloric acid) lowers high pH and total alkalinity so chlorine works effectively and water stays clear and comfortable. For safety and compliance reasons, Benchmark Pool Supply sells this product in-store only at our Fresno and Clovis locations.
What Is Muriatic Acid?
Muriatic acid is a diluted form of hydrochloric acid (HCl). In swimming pools, it’s used to:
- Lower high pH (above ~7.8)
- Reduce total alkalinity (TA)
- Help remove calcium scale on tile and plaster
- Prepare surfaces for certain cleaning procedures
When applied correctly, muriatic acid supports clear water, efficient sanitation, and protects equipment from mineral deposits.
Why Use Muriatic Acid in Pool Maintenance?
High pH and alkalinity can cause:
- Cloudy water and dull appearance
- Reduced chlorine effectiveness
- White calcium scale on tile and heaters
- Eye and skin discomfort
Balancing pH ~7.2–7.8 and TA around 80–120 ppm keeps your system efficient and comfortable.
How to Safely Add Muriatic Acid to Your Pool
Safety first: Wear eye protection, chemical-resistant gloves, and closed shoes. Work outdoors or in a very well-ventilated area.
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Test your water. Measure pH and TA with reliable tools.
→ Water Testing Kits - Determine dosage. Bring a water sample to Benchmark Pool Supply for an expert recommendation. Dose depends on pool volume, current readings, and acid strength.
- Pre-dilute if needed. In a clean plastic bucket of water, add acid to water—never water to acid.
- Add slowly in the deep end with the pump running, away from fittings and lights. Avoid splashing.
- Circulate and retest. After several hours of circulation, retest and repeat small adjustments until pH returns to ~7.2–7.8.
When can I swim? Once pH tests back within range and the water is circulating normally.
Muriatic Acid vs. Dry Acid (Sodium Bisulfate)
| Feature | Muriatic Acid | Dry Acid (Sodium Bisulfate) |
|---|---|---|
| Form | Liquid (HCl) | Granular powder |
| Strength | Very strong | Milder |
| Fumes | Noticeable | Minimal |
| Adds sulfates? | No | Yes |
| Cost efficiency | High | Moderate |
Takeaway: Many service pros favor muriatic acid for efficiency and to avoid sulfate accumulation; dry acid suits tight indoor spaces or specific surface constraints.
Cloudy Water? Acid Isn’t a Clarifier
If the pool is cloudy, start with filtration and a clarifier to bind fine particles so the filter can remove them.
Use muriatic acid specifically when pH/TA are high; it is not a direct fix for suspended debris.
Tile & Scale Removal
For light calcium deposits on tile:
- Mix 1 part acid : 10 parts water.
- Apply carefully with proper PPE and rinse immediately.
- Avoid full plaster acid washing unless professionally advised—it removes a thin plaster layer.
Need supplies? Visit Tile & Scale Removers.
Common Mistakes to Avoid
- Never mix with chlorine or oxidizers (risk of toxic gas).
- Do not add acid directly into skimmers/feeders (risk of concentrated corrosion).
- Avoid over-treating; keep pH within range to protect surfaces and equipment.
In-Store Only — Fresno & Clovis
Muriatic acid is not available for online purchase. We sell it in-store to ensure safe transport and proper handling guidance. Bring your water sample and pool volume for a precise dose and PPE recommendations.
FAQs
Is muriatic acid safe for pool water?
Yes—when measured and handled correctly. It’s widely used by professionals to control pH and alkalinity.
Can muriatic acid lower total alkalinity?
Yes. Acid addition combined with aeration will reduce TA over time while keeping pH in range.
Can I use muriatic acid to clean tile scale?
Yes, for light scale in a diluted solution with PPE. Rinse immediately and avoid long contact with grout or plaster.
How often should I add muriatic acid?
Frequency depends on your fill water and sanitizer type. Many pools need small, regular adjustments. Test weekly.
Where can I buy muriatic acid near me?
At Benchmark Pool Supply in Fresno and Clovis. It is available in-store only.
