Pool Salt Calculator: How Much Salt Should You Add?



Need to know how much salt to add to your pool?

This article will show you how to figure out the amount of salt to add to your water, including a simple pool salt calculator.

If you already know your current salt level and pool capacity, you don’t need to follow steps below, just go straight to the calculator.

What’s the Ideal Salt Level for a Pool?

The ideal salt level for a saltwater pool is 3,200 parts per million (ppm), but anywhere between 2,700 and 3,400 ppm is also acceptable.

Anything below 2,700 ppm and the salt generator likely won’t be able to make enough chlorine to keep your water properly sanitized.

Much more than 3,400 ppm and your water can become corrosive to metal. You may also begin to taste the salt contents of the water during your swim, which might be unpleasant for some people.

How to Calculate How Much Salt to Add

Now that you know what to aim for in terms of salt level, you’ll need to figure out how much salt to add to your water to reach that number.

Here are the steps the follow:

Step 1. Get Your Pool Water Volume

First, you need to figure out the amount of water in your pool.

If you built your swimming pool from scratch, you’ll probably know this number like the back of your hand. In that case, skip to the next and final step.

If you don’t know the capacity of your pool, measure the length, width, and depth of your swimming pool in feet. If you have a round pool, just measure the furthest distance from one side to the other.

Once you have those measurements, you can use the calculator below to get a close-enough estimate of your pool volume.

Step 2. Get Your Current Salt Level

Next, you need to test your water to find out your salt level.

You can use salt test strips for this but they aren’t quite as accurate as using a liquid testing kit for salinity. We recommend the Taylor Sodium Chloride Test Kit if you don’t already have one.

Another option is to take some of your water to a pool store for testing, as many will even do this for free (on the assumption that you’ll likely buy something from them afterward).

Either way, you’ll want to take an elbow-deep sample from the deep end of your swimming pool for testing. This patch of water will better reflect the salt content of your pool as a whole.

Step 3. Use Our Pool Salt Calculator

Finally, calculate how much salt you need to add to your pool.

There’s also some math involved with this one so we built another calculator to simplify the process. All you need to do is plug your current salt level and pool volume into it to get a result.

Curious how it works?

  • Your current salt level is subtracted from the target salt level to get the desired increase.
  • Your pool capacity is then multiplied by the desired increase.
  • The result is divided by 120,000 (because 1 lb of salt raises salinity by 120 ppm per 1,000 gallons).

How To Add Salt To Your Saltwater Pool

Adding salt to a pool is pretty much as easy as it sounds, but there are a few nuances to be aware of.

Here’s how to do it step-by-step:

  1. Turn off your chlorine generator. This will allow the salt to be evenly distributed throughout the pool by the pump.
  2. Pour the salt directly into the pool but away from the skimmer.
  3. Keep the pump running for at least 24 hours. Large pools may require up to 48 hours for the dissolved salt to fully disperse.
  4. Brush the pool floor to lift up any salt that managed to escape circulation and decided to settle.
  5. Retest your salinity level to make sure you calculated correctly, and repeat this process by adding more salt if needed.

Pro tip: Only use sodium chloride with a purity of 99% or higher. Any other salt will not only make the chlorine less effective, but you run the risk of discoloring your pool finish, surfaces, and fittings of your pool.

How To Lower Your Salt Level

If you’ve miscalculated and added too much salt, the most effective way to reduce your salt level is through dilution.

Diluting your pool water involves partially draining the pool and replacing it with fresh water to lower the overall salt concentration. If you don’t already know how much to dilute, refer back to the calculator above.

Here’s how to do it step-by-step:

  1. Turn off the pool pump to protect your equipment from damage, as air can be sucked in through the skimmer when the water level is low.
  2. Attach a hose to a submersible pump, place the pump in the deep end of your pool, and run the hose to a sewer or safe drainage point.
  3. Before draining any water, mark the current water level so you know exactly how much fresh water you need to put back in.
  4. If your submersible pump has a flow meter, drain until it measures exactly the number of gallons you need. If it doesn’t have a flow meter, you’ll need to estimate as best you can based on percentage.
  5. Once it’s drained enough, connect a garden hose to your backyard spigot and refill the pool to its previous water level (as marked).
  6. Turn your pump back and wait for it to circulate the fresh water. This may take several hours depending on the size of your pool.
  7. Retest your salinity level to make sure you diluted enough, and repeat this process if it’s still too high.

Note: If your salt level is only slightly above where you want it to be, waiting it out by letting your chlorinator work through it might be an easier solution.

The Bottom Line

To figure out how much salt to add to a pool, it’s best to use a simple calculator like the one provided in this article.

As long as you know your current salinity level and how much water your swimming pool holds, you’ll know exactly how much salt you need with a reasonable degree of accuracy.

Categories: Pool Care, Pool Chemistry