Hot Tub Water Chemistry 101: Balancing pH, Sanitizers & More for Crystal-Clear Soaks

Hot Tub Water Chemistry 101: Balancing pH, Sanitizers & More for Crystal-Clear Soaks

A perfectly functioning hot tub isn’t just about powerful jets or cozy seating—it’s also about what you don’t see: the water chemistry. Balanced water is essential for your safety, the performance of your spa, and the longevity of its components. In this guide, we’ll break down the key elements of water chemistry and how to maintain crystal-clear water with confidence.

Why Water Chemistry Matters

Keeping your spa’s water in balance prevents a host of issues, including skin irritation, equipment corrosion, cloudy water, and the growth of bacteria or algae. More importantly, it protects your investment by helping spa components last longer saving you money in the long run.

The Five Key Water Parameters

Let’s look at the five main factors to keep in check:

1. pH Level (Ideal: 7.2–7.8)

  • Too Low? Water becomes acidic, potentially corroding metal parts and irritating skin and eyes.

  • Too High? Can lead to cloudy water and reduce the effectiveness of sanitizers.

  • How to Adjust: Use a pH increaser or decreaser. Always test your water before and after treatment.

2. Total Alkalinity (Ideal: 80–120 ppm)

  • Works like a buffer for pH. If alkalinity is off, your pH levels can swing rapidly.

  • Use an alkalinity increaser to raise levels. Lowering it usually involves using a pH reducer.

3. Sanitizers (Chlorine or Bromine)

  • Chlorine: Fast-acting and commonly used.

  • Bromine: Gentler on skin, better for high-temperature water, and lasts longer.

  • Tip: Never mix the two in your spa! Choose one system and stick with it.

4. Calcium Hardness (Ideal: 150–250 ppm)

  • Too Low? Water can become corrosive to spa components.

  • Too High? You risk scaling on surfaces and internal plumbing.

  • Use a calcium hardness increaser as needed, or dilute high-calcium water with fresh, softer water.

5. Total Dissolved Solids (TDS)

  • Measures all the minerals, chemicals, and byproducts in your water.

  • Too High? Water may look dull or feel sticky. When TDS is above 1,500 ppm, it’s time to drain and refill.

Common Water Issues & How to Fix Them

  • Cloudy Water: Caused by imbalanced pH, dirty filters, or high TDS. Shock the water and check filtration.

  • Foam Buildup: Caused by soaps, lotions, or low calcium. Use an anti-foam agent and rinse before soaking.

  • Algae or Green Water: Often the result of low sanitizer levels. Shock treatment and good filtration help.

  • Itchy Skin or Eyes: Usually due to low pH or high sanitizer levels. Test and adjust accordingly.

Hot Tub Water Maintenance Tips

  • Test your water 2–3 times a week using test strips or a digital test kit.

  • Add chemicals gradually, allowing each to fully circulate before retesting.

  • Clean your filters weekly and replace them every 12–18 months.

  • Drain and refill your spa every 3–4 months to maintain freshness.

 

Need help finding the right products or have questions about your water? Contact us today, we’re here to help you make the most of your spa experience.

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