How Do I Prevent Scale from Forming in My Hot Tub?

Regularly test your water for calcium hardness and keep it within the recommended range (150-250 ppm). Use a scale preventer if necessary.

What is Scale in a Hot Tub?

Scale is a hard, chalky deposit that forms when minerals, such as calcium and magnesium, are left behind in the water. This typically happens when water is heated and the minerals become less soluble, causing them to settle on the surfaces of the hot tub. Over time, scale can build up on the walls, plumbing, and heater of your hot tub, leading to clogs, reduced heater efficiency, and even damage to the equipment. Scale buildup can also cause cloudy water and an unpleasant feeling when soaking in the tub.

Common Causes of Scale Formation

• Hard water: Water with high levels of calcium and magnesium is considered “hard,” and it is more likely to form scale when heated.
  

• High water temperature: The hotter the water in your hot tub, the more likely it is that minerals will precipitate out of the water and form scale deposits.
  

• High pH and alkalinity: Water that is too alkaline can promote the formation of scale. If the pH and alkalinity levels are out of balance, it can lead to increased mineral buildup.
  

How to Prevent Scale from Forming in Your Hot Tub

Now that you understand what scale is and what causes it, let’s dive into the steps you can take to prevent it from forming in your hot tub.

1. Use a Water Softener

One of the best ways to prevent scale from forming in your hot tub is by using a water softener. Water softeners remove excess calcium and magnesium from the water, making it less likely for these minerals to form scale. If your area has hard water, installing a water softener is highly recommended.

• How to install: A water softener is usually installed before the water enters the hot tub’s plumbing system. You can buy an inline water softener that connects to your garden hose and filters the water as you fill the tub.
  

• Benefits: Using a water softener will not only reduce scale buildup but can also help extend the life of your hot tub and make the water feel softer and more comfortable.
  

• Additional Tip: If you have a saltwater pool, consider installing a separate water softener to prevent excessive salt levels in your hot tub.
  

2. Regularly Test and Balance the Water Chemistry

Maintaining proper water chemistry is crucial in preventing scale formation. When your hot tub’s water chemistry is out of balance, it can lead to an increased likelihood of scale buildup. Follow these steps to ensure the water chemistry remains in check:

• Test your water regularly: Use a test strip or a water testing kit to check the levels of pH, alkalinity, and calcium hardness.
  

• Balance the pH and alkalinity: Ideally, the pH of your hot tub water should be between 7.2 and 7.8, and the alkalinity should be between 80 and 120 ppm (parts per million). If either of these levels is too high, scale can form more easily.
  

• Adjust the calcium hardness: Calcium hardness levels should be between 150 and 250 ppm. If the levels are too high, scale can form more easily. If they’re too low, your water may become corrosive and damage your hot tub.
  

• Pro Tip: Invest in a good quality pool and spa water test kit to make this process easier. Regular testing ensures your hot tub stays in top shape.
  

3. Use a Scale Preventer or Sequestering Agent

In addition to balancing your water chemistry, you can use a scale preventer or sequestering agent to help prevent the minerals in your hot tub water from bonding to surfaces and forming scale.

• How it works: A scale preventer works by binding with the minerals in the water, preventing them from forming solid deposits on your hot tub surfaces.
  

• When to use: Add a sequestering agent to your hot tub water during regular maintenance or when you notice an increase in calcium hardness levels.
  

• Regular use: For best results, use a scale preventer according to the manufacturer’s instructions, typically once every month or after every water change.
  

• Additional Tip: Make sure to use a non-chlorine-based agent if you’re using a chlorine-free sanitizer.
  

4. Drain and Refill Your Hot Tub Regularly

Draining and refilling your hot tub regularly is a good way to prevent scale buildup. Over time, the water in your hot tub can accumulate minerals and chemicals, which can increase the chances of scale formation. Draining and replacing the water helps to flush out any accumulated minerals.

• When to drain: Plan to drain and refill your hot tub every 3 to 4 months, depending on usage and water quality.
  

• How to drain: Always follow the manufacturer’s instructions when draining your hot tub to avoid damaging the system.
  

• Pro Tip: Before refilling, use a hose filter to remove any contaminants in the water.
  

5. Clean Your Hot Tub Filters

Your hot tub’s filters play a critical role in trapping debris and minerals, which can contribute to scale buildup. Cleaning or replacing the filters regularly ensures that your hot tub’s filtration system is functioning efficiently.

• How often to clean: Clean your filters every 4 to 6 weeks, or more frequently if you use your hot tub often.
  

• How to clean: Remove the filters and rinse them with a hose to remove debris. You can also soak them in a filter-cleaning solution to remove oil and mineral buildup.
  

• Pro Tip: Replace your filters every year to ensure that they continue to function effectively.
  

6. Maintain Proper Water Temperature

Keeping your hot tub’s water temperature at the proper level can help prevent scale formation. Water that is too hot increases the likelihood of minerals precipitating out of the water.

• Ideal temperature: The recommended temperature for hot tubs is between 100°F and 104°F. Water temperatures above this can increase the chances of scaling.
  

• Avoid overheating: Keep an eye on your hot tub’s thermostat and avoid setting it to unnecessarily high temperatures. Overheating may lead to unnecessary mineral buildup.
  

How to Remove Existing Scale in Your Hot Tub

If you already have scale buildup in your hot tub, don’t worry. You can remove it with a few simple cleaning methods:

• Use a scale remover: There are cleaning products specifically designed to dissolve scale deposits. Apply a scale remover according to the manufacturer’s instructions.
  

• Scrub with a soft brush: For stubborn scale, gently scrub the affected areas with a soft brush to loosen the deposits.
  

• Clean your filter: After removing the scale, make sure to clean your hot tub filter to remove any residual debris.
  

Preventing Future Scale Build-up

Once you've cleared your hot tub of any existing scale, you can further reduce the chances of future buildup by taking the following preventative measures:

• Install a filter bypass: Some hot tub owners install a filter bypass system that helps prevent minerals from entering the water in the first place.
  

• Monitor water levels: Keeping your water levels consistent can help prevent scale from forming due to evaporation.

• Seasonal checks: Perform seasonal checks to keep your hot tub’s water in optimal condition.