Can I Use Pool pH Increaser in My Spa? Safe Chemical Guide

Tools & Supplies Needed

Find on Amazon: Taylor K-2006C Test Kit , Spa pH Increaser , Digital Test Strips

Quick Answer

Yes, you can absolutely use pool pH increaser in your spa. Pool pH increaser and spa pH increaser contain the same active ingredient - sodium carbonate (also called soda ash). The key difference is adjusting the dosage for your spa's much smaller water volume compared to a swimming pool.

Diagnosing Your Spa's pH Issue

First, let's diagnose what's happening with your spa's pH levels. Test your current pH using a reliable test kit like the Taylor K-2006C or test strips specifically designed for spas. Your spa's ideal pH range is 7.2-7.6, with 7.4-7.5 being optimal for bather comfort and equipment protection.

Low pH (below 7.2) can cause:

• Eye and skin irritation for bathers
• Corrosion of metal components like heaters and pumps
• Etching of spa surfaces
• Reduced sanitizer effectiveness

Using Pool pH Increaser in Your Spa

Understanding the Chemistry

Both pool and spa pH increasers typically contain sodium carbonate (Na₂CO₃), which raises both pH and total alkalinity. Some products may contain sodium bicarbonate (baking soda) as well, but sodium carbonate is the primary pH-raising chemical. This means the pool version will work identically in your spa.

Calculating the Correct Dosage

Here's where you need to be careful. Pool pH increaser dosing instructions are designed for pools containing 10,000-30,000+ gallons, while most residential spas hold 300-500 gallons. Never use the pool dosage recommendations directly.

For spa dosing with sodium carbonate:

• Add 1/4 teaspoon per 100 gallons to raise pH by approximately 0.2 units
• For a 400-gallon spa with pH of 6.8, add 1 teaspoon to target pH 7.4
• Always start with less - you can add more, but you can't remove excess chemical

Step-by-Step Application Process

1. Test current water chemistry: Measure pH, total alkalinity, and sanitizer levels before adding any chemicals
2. Calculate needed dosage: Determine your spa's exact volume and calculate the appropriate amount of pH increaser
3. Pre-dissolve the chemical: Mix the measured pH increaser in a clean bucket with spa water to ensure complete dissolution
4. Add with circulation running: Pour the dissolved solution slowly around the spa perimeter with jets operating
5. Allow circulation time: Run pumps for at least 30 minutes to ensure complete mixing
6. Retest and adjust: Test pH again after 30 minutes and add more if needed
7. Check total alkalinity: Sodium carbonate will also raise TA, so monitor this parameter

Safety Considerations

Important safety reminders when using pool chemicals in your spa:

• Always read the product label completely, even though you're adjusting the dosage
• Wear safety glasses and gloves when handling dry chemicals
• Never mix different chemicals together
• Store chemicals in original containers away from heat and moisture
• Keep spa area well-ventilated during chemical addition
• Wait at least 30 minutes before entering the spa after chemical addition

Troubleshooting Common Issues

pH Won't Stay Raised

If your pH keeps dropping after treatment, check your total alkalinity. Low TA (below 80 ppm) acts as a pH buffer. You may need to raise alkalinity first using sodium bicarbonate (baking soda) at 1.5 tablespoons per 100 gallons to raise TA by 10 ppm.

Cloudy Water After Treatment

Adding too much pH increaser too quickly can cause temporary cloudiness. Ensure your sanitizer levels are adequate (3-5 ppm free chlorine or 3-8 ppm bromine) and run circulation continuously until water clears.

pH Overshooting Target

If pH rises above 7.8, you'll need to lower it using spa pH decreaser (sodium bisulfate) or muriatic acid. For spas, use 1/4 teaspoon sodium bisulfate per 100 gallons to lower pH by 0.2 units.

Alternative Options

While pool pH increaser works perfectly, you might also consider:

• Spa-specific pH increaser: Same ingredients but with spa-appropriate dosing instructions
• Pure sodium carbonate: Available at hardware stores as washing soda (ensure it's pure sodium carbonate)
• Liquid pH increasers: Easier to dose accurately for small spa volumes

The bottom line: pool pH increaser is chemically identical to spa pH increaser, making it perfectly safe and effective for your spa when dosed correctly for the smaller water volume.