How Do I Prevent Scale on Pool Heaters

Keep calcium hardness levels within the recommended range of 200-400 ppm and clean your heater regularly to prevent scaling.

What Is Scale and Why Is It a Problem?

Scale is primarily made up of calcium and other minerals found in hard water. When the pool heater heats the water, the minerals in the water become less soluble and begin to precipitate out, forming scale deposits on surfaces like the heat exchanger. Over time, these deposits can cause several issues:

• Reduced heat transfer: Scale buildup on the heat exchanger makes it harder for the heater to transfer heat efficiently, causing it to work harder and use more energy.
  

• Increased energy costs: Because the heater is less efficient, it requires more energy to maintain the desired water temperature, leading to higher utility bills.
  

• Damage to the heater: Scale buildup can clog pipes, damage internal components, and eventually lead to complete heater failure if left unchecked.
  

Preventing scale buildup in your pool heater is crucial to maintaining its efficiency and extending its lifespan.

How Does Scale Form on Pool Heaters?

Scale forms when hard water is heated in the pool heater, which causes minerals like calcium and magnesium to precipitate out of the water and adhere to surfaces. This process is accelerated by high water temperatures, which is why heaters are particularly prone to scale buildup.

• Calcium hardness: The level of calcium in the water plays a key role in scale formation. Water with high calcium hardness (above 400 ppm) is more likely to cause scaling.
  

• High water temperatures: The higher the water temperature in the heater, the more likely scale will form. Pool heaters often operate at temperatures above the typical solubility threshold for calcium and other minerals.
  

• Poor water circulation: Inadequate water flow or filtration can leave minerals suspended in the water, increasing the chances of scale formation.
  

How to Prevent Scale Buildup on Pool Heaters

Preventing scale buildup in your pool heater is a matter of managing water chemistry, regular maintenance, and making sure the heater operates efficiently. Here are some of the best ways to prevent scale:

1. Maintain Proper Calcium Hardness Levels

One of the most effective ways to prevent scale formation is by controlling the calcium hardness levels in your pool water.

• Ideal range: The ideal calcium hardness level for pool water is between 200 and 400 ppm.
  

• Test regularly: Test your pool water regularly to monitor calcium hardness. You can use a pool test kit or take a water sample to your local pool supply store for testing.
  

• Adjust calcium levels: If the calcium hardness is too high, you can lower it by partially draining the pool and refilling it with fresh water or by using a calcium-reducing agent.
  

2. Use a Scale Preventer or Sequestering Agent

Scale preventers or sequestering agents are chemicals designed to prevent minerals like calcium from precipitating out of the water and forming scale. These products bind to the minerals, keeping them in a dissolved state.

• What to use: Look for a sequestering agent that is specifically designed for pools with hard water. These products are available at pool supply stores.
  

• How to use it: Follow the manufacturer’s instructions for adding the scale preventer to your pool. Typically, these products are added directly to the pool water, and you may need to reapply them periodically.
  

• Regular use: For pools with consistently high calcium levels, use a sequestering agent regularly to keep the water in balance.
  

3. Monitor and Adjust pH and Alkalinity Levels

pH and alkalinity levels also play a role in scale formation. When the pH is too high, the water becomes more alkaline, which promotes scale buildup. Similarly, high alkalinity can lead to a similar effect.

• Ideal pH range: Maintain a pH level between 7.4 and 7.6.
  

• Ideal alkalinity range: Keep your pool’s total alkalinity between 80 and 120 ppm.
  

• How to adjust: If the pH or alkalinity is too high, use pH decreaser or muriatic acid to lower it. For low pH, use a pH increaser (soda ash).
  

4. Ensure Proper Water Circulation and Filtration

Good water circulation and filtration help prevent scale buildup by ensuring that the water is properly filtered, and minerals don’t settle in the heater or on pool surfaces.

• Regularly clean the filter: A dirty filter can cause water to circulate poorly, leaving minerals suspended in the water. Clean or replace the filter as needed.
  

• Run the pump regularly: Make sure the pool pump runs for at least 8 to 12 hours a day to ensure good circulation. This is particularly important during the heating season.
  

5. Lower the Temperature on Your Pool Heater

While it’s tempting to keep the pool water warm during cooler months, running the heater at high temperatures can accelerate scale formation.

• Optimal temperature: Keeping the pool heater at a moderate temperature (around 78°F to 82°F) can help reduce scale formation while still keeping the water comfortable.
  

• Avoid overheating: If possible, avoid running the heater at its highest settings for prolonged periods.
  

6. Regularly Flush the Heater

Flushing the heater helps remove any scale buildup and ensures that the system is working efficiently.

• How to flush: Consult your heater’s manual for instructions on how to flush the system. Typically, this involves turning off the power, draining the water, and running water through the heater to dislodge any scale.
  

• Frequency: Flush your pool heater at least once a year, especially if you live in an area with hard water.
  

How to Remove Scale From Pool Heaters

If scale has already built up in your pool heater, it’s essential to remove it as soon as possible to restore the heater’s efficiency. Here’s how to do it:

1. Turn off the power: Before you begin cleaning the heater, turn off the power to avoid any electrical issues.
   

2. Drain the water: Drain the water from the pool heater to prevent any accidental spillage.
   

3. Use a descaling solution: Apply a descaling solution to the affected areas of the heater. These solutions are designed to break down calcium deposits and other minerals that have built up.
   

4. Scrub the surfaces: Use a soft brush to gently scrub away any remaining scale after the descaling solution has been applied.
   

5. Flush the system: After removing the scale, flush the heater with fresh water to remove any remaining debris.
   

6. Refill the pool: Once the heater has been cleaned, refill the pool with fresh water and check the water chemistry to ensure everything is in balance.
   

How to Prevent Scale Buildup in Your Pool Heater

To ensure that scale doesn’t become a recurring issue, you need to take proactive measures to maintain water quality and heater efficiency:

• Regularly test your pool water: Monitor calcium hardness, pH, and alkalinity levels and adjust them as necessary to keep your water in balance.
  

• Use sequestering agents regularly: If you live in an area with hard water, use a sequestering agent regularly to prevent scale buildup.
  

• Perform routine maintenance: Keep your filter clean, and run the pump regularly to ensure good water circulation and filtration.
  

• Lower water temperature: Keep the water temperature at a moderate level to reduce the chance of scale forming in the heater.

• Flush your heater: Regularly flush the heater to remove any accumulated scale and prevent it from building up over time.