How to Raise Alkalinity in Your Hot Tub

Total alkalinity is what stabilizes pH in your hot tub water. When alkalinity drops too low, pH can swing wildly, leading to damage, discomfort, and cloudy water. Keeping it balanced is key to water quality and equipment longevity.

Effects of Low Alkalinity

• Corrosive water that damages surfaces and equipment

• Fluctuating pH that makes water hard to balance

• Eye and skin irritation for bathers

• Cloudy or foamy water

Ideal Alkalinity Levels

For hot tubs, the ideal alkalinity range is between 80 and 120 parts per million (ppm). Testing and adjusting regularly helps keep it in this range.

Testing Alkalinity

• Use test strips or a liquid test kit to measure total alkalinity.

• Test at least once a week, or more often with heavy use.

Step-by-Step Guide to Raising Alkalinity

Step 1: Test the Water

• Take a water sample and check the current alkalinity level.

• If it is below 80 ppm, it needs to be raised.

Step 2: Choose an Alkalinity Increaser

• Sodium bicarbonate (baking soda) is commonly used.

• Available as a pool and spa-specific product at supply stores.

Step 3: Calculate the Amount Needed

• Follow the instructions on the product label.

• Typically, 1.5 pounds of sodium bicarbonate raises 10,000 gallons of water by about 10 ppm.

Step 4: Add the Alkalinity Increaser

• Turn on the jets to circulate water.

• Sprinkle the recommended amount of powder evenly over the surface.

• Let the water circulate for 15 to 30 minutes.

Step 5: Retest the Water

• After about 30 minutes, test again.

• Repeat the process if the level is still below the desired range.

Tips for Maintaining Alkalinity

Regular Monitoring

• Keep a schedule and test water weekly.

• Make small adjustments as needed to avoid large swings.

Balance pH and Alkalinity Together

• Always adjust alkalinity first before correcting pH.

• Alkalinity acts as a buffer for pH stability.

Use the Right Products

• Avoid household baking soda unless in a pinch; use spa-grade increaser when possible.

Advanced Tips for Experienced Owners

1. Invest in a digital water tester for precise measurements.

2. Keep detailed records of your water chemistry to spot trends.

3. Be mindful of how water additions and heavy usage can lower alkalinity.

4. Drain and refill your hot tub periodically to reset water chemistry.

Common Mistakes to Avoid

• Adding too much increaser at once, which can overshoot the target.

• Neglecting to run the jets during chemical addition.

• Forgetting to retest and adjust in small increments.

• Ignoring pH while adjusting alkalinity.

By following these steps and tips, you can raise alkalinity in your hot tub properly and maintain a comfortable, safe, and balanced water environment. Regular maintenance keeps your spa enjoyable and worry-free for everyone.