What Happens If Salt Level Is Too Low In Pool?

Saltwater pools are becoming more popular among pool owners who want to enjoy the benefits of chlorine without the harsh chemicals. Saltwater pools use a salt chlorine generator to convert salt into chlorine, which sanitizes the water and keeps it clear and safe.

However, maintaining the right salt level in a saltwater pool is crucial for its proper functioning and performance. In this article, we will explain what happens if the salt level is too low in a pool, how to test and adjust it, and some tips to prevent salt loss.

what happens if salt level is too low in pool

Effects of Low Salt Levels in Pool

The ideal salt level for a saltwater pool is between 2,700 and 3,400 parts per million (ppm), with 3,200 ppm being the optimal range. If the salt level drops below 2,700 ppm, the salt chlorine generator will not be able to produce enough chlorine to sanitize the pool effectively. This can lead to several problems, such as:

  • Algae growth: Algae are microscopic plants that thrive in warm and nutrient-rich water. Without enough chlorine to kill them, algae can quickly multiply and turn the pool water green, cloudy, or slimy. Algae can also clog the filter and damage the pool surfaces and equipment.
  • Bacteria and viruses: Bacteria and viruses are harmful microorganisms that can cause various infections and diseases, such as ear infections, skin rashes, eye irritation, diarrhea, and more. Without enough chlorine to disinfect the water, bacteria and viruses can easily contaminate the pool and pose a health risk to swimmers.
  • Corrosion: Corrosion is the deterioration of metal parts due to chemical reactions with water and oxygen. Without enough chlorine to balance the water chemistry, the water can become acidic and corrode the metal components of the pool, such as ladders, rails, heaters, pumps, and pipes. Corrosion can also cause stains and discoloration on the pool surfaces.
  • Low pH: pH is a measure of how acidic or basic the water is. The ideal pH range for a pool is between 7.2 and 7.8. If the salt level is too low, the water can become too acidic and lower the pH. Low pH can cause eye and skin irritation, damage the pool surfaces and equipment, and reduce the effectiveness of chlorine.

How to Test and Adjust Salt Level in Pool

To avoid these problems, it is important to test and adjust the salt level in a pool regularly. There are different methods to test the salt level in a pool, such as:

  • Salt chlorine generator: Most salt chlorine generators have a digital display that shows the current salt level in ppm. However, this reading may not be accurate due to factors such as temperature, calibration, or sensor malfunction. Therefore, it is recommended to verify the reading with another method at least once a month.
  • Salt test kit: A salt test kit is a simple and inexpensive way to measure the salt level in a pool. It usually consists of a plastic strip or tablet that changes color when dipped in a water sample. The color is then compared to a chart that indicates the corresponding salt level in ppm.
  • Salt meter: A salt meter is an electronic device that measures the electrical conductivity of the water sample. The higher the conductivity, the higher the salt level. A salt meter gives an instant and precise reading of the salt level in ppm.

To adjust the salt level in a pool, you need to either add more salt or replace some water with fresh water. The amount of salt or water needed depends on the current and desired salt levels and the volume of the pool. You can use online calculators to estimate how much salt or water you need to add or replace.

To add more salt to a pool:

  • Use pool-grade salt that is at least 99% pure and free of additives or impurities.
  • Dissolve the salt in a bucket of warm water before adding it to the pool.
  • Pour the salt solution evenly around the perimeter of the pool while the pump is running.
  • Wait at least 24 hours for the salt to circulate and dissolve completely before testing again.

To replace some water with fresh water:

  • Drain some water from the pool using a hose or a submersible pump.
  • Refill the pool with fresh water from a tap or a well.
  • Test and balance the other chemical parameters of the pool, such as pH, alkalinity, calcium hardness, and stabilizer.
  • Wait at least 24 hours for the water to mix thoroughly before testing again.

Tips to Prevent Salt Loss

Salt does not evaporate or degrade over time, so once you add it to your pool, it stays there until you remove it. However, there are some factors that can cause salt loss, such as:

  • Splash-out: Splash-out is the water that is lost due to splashing, spilling, or overflowing from the pool. Splash-out can also carry salt with it, especially if the pool is near the edge or has a fountain or a waterfall feature.
  • Backwashing: Backwashing is the process of cleaning the filter by reversing the water flow and flushing out the dirt and debris. Backwashing can also remove some water and salt from the pool.
  • Leakage: Leakage is the water that is lost due to cracks, holes, or defects in the pool structure or plumbing. Leakage can also cause salt loss and damage the pool and its surroundings.
  • Rainfall: Rainfall is the water that is added to the pool due to precipitation. Rainfall can dilute the salt level and lower the water chemistry of the pool.

To prevent salt loss, you can follow these tips:

  • Use a pool cover to reduce evaporation and splash-out.
  • Minimize backwashing by keeping the filter clean and maintaining proper water circulation.
  • Check for and repair any leaks in the pool or its equipment.
  • Drain some water from the pool after heavy rainfall and adjust the salt level accordingly.


Saltwater pools are a great alternative to traditional chlorine pools, but they require proper maintenance and care. Keeping the right salt level in a pool is essential for the performance of the salt chlorine generator and the quality of the water. If the salt level is too low, it can cause algae growth, bacteria and viruses, corrosion, low pH, and other problems.

To avoid these issues, you should test and adjust the salt level regularly using a salt chlorine generator, a salt test kit, or a salt meter. You should also prevent salt loss by using a pool cover, minimizing backwashing, checking for leaks, and draining some water after rainfall.