How Do I Remove Calcium Buildup from Hot Tub Surfaces?

Use a non-abrasive cleaner and a soft brush or cloth to scrub away calcium deposits. Regular water balancing can prevent future buildup.

What Causes Calcium Buildup in a Hot Tub?

Calcium deposits form when your water has high mineral content, especially calcium and magnesium. This often happens due to:

• Hard Water: Water with high calcium levels increases scaling risks.
  

• High pH and Alkalinity: Imbalanced water chemistry speeds up calcium deposits.
  

• Heat Exposure: Warm water causes minerals to harden and stick to surfaces.
  

• Evaporation: As water evaporates, calcium stays behind and forms a crust.
  

The good news is that proper maintenance can help prevent and remove scaling before it becomes a bigger problem.

How to Remove Calcium Buildup from Hot Tub Surfaces

1. Drain and Inspect the Hot Tub

Before scrubbing, lower the water level or fully drain your hot tub. This will make it easier to reach affected areas and remove stubborn deposits.

• If scaling is mild, you may be able to clean without draining.
  

• For severe buildup, a full drain-and-clean is recommended.
  

2. Use a Hot Tub Cleaner or Vinegar Solution

Mild calcium buildup can often be removed with common household products.

• White Vinegar: Mix equal parts vinegar and water. Apply to affected areas and scrub gently.
  

• Baking Soda Paste: Combine baking soda with water to create a mild abrasive cleaner.
  

• Hot Tub Surface Cleaner: Use a non-abrasive, pH-balanced cleaner made for hot tubs.
  

Let the solution sit for a few minutes before scrubbing.

3. Scrub with a Non-Abrasive Sponge

Avoid scratching your hot tub’s surface by using the right tools.

• Soft Sponges or Cloths: Best for light buildup.
  

• Melamine Sponge (Magic Eraser): Works well for tougher spots.
  

• Plastic Scrubber Brush: Use for stubborn calcium deposits.
  

Scrub in circular motions and apply more cleaner as needed.

4. Tackle Stubborn Scaling with a Pumice Stone

For thick calcium deposits, a pumice stone can be effective. Keep these tips in mind:

• Always keep the surface and pumice stone wet to prevent scratching.
  

• Gently rub the buildup until it breaks down.
  

• Avoid using pumice on acrylic or fiberglass hot tubs, as it can cause damage.
  

5. Flush the Plumbing System

Calcium buildup doesn’t just affect visible surfaces, it can also clog your pipes and jets.

• Use a hot tub line flush cleaner to remove internal scaling.
  

• Run the jets for at least 15-30 minutes to circulate the cleaner.
  

• Drain and rinse the tub before refilling with fresh water.
  

6. Refill and Balance the Water

Once your hot tub is clean, refill it with fresh water. Test and adjust the following levels:

• pH: 7.2 - 7.8
  

• Alkalinity: 80 - 120 ppm
  

• Calcium Hardness: 150 - 250 ppm
  

Proper water balance reduces the chances of calcium buildup returning.

How to Prevent Calcium Buildup in Your Hot Tub

Once you’ve removed scaling, take steps to keep it from coming back.

• Use a Water Softener: If your water is naturally hard, a pre-filter can reduce calcium levels before filling your tub.
  

• Monitor Water Chemistry: Test and adjust pH, alkalinity, and calcium hardness weekly.
  

• Add a Scale Inhibitor: Special chemicals help prevent mineral deposits from sticking to surfaces.
  

• Wipe Down Surfaces Regularly: After each soak, wipe down your hot tub walls to remove any residue.
  

• Keep Your Filter Clean: A dirty filter won’t catch calcium particles effectively, so clean or replace it as needed.
  

Keeping your hot tub in good shape requires regular maintenance, but removing calcium buildup doesn’t have to be a difficult task. By following these steps, you can keep your hot tub surfaces clean and extend the life of your spa.