Pool Salt Calculator (Litres / Metric) - How Much Salt To Add To Pool In Australia?

Have you just taken a salinity reading of your pool water and realised that it's outside the recommended range?

Use this metric pool salt calculator to work out exactly how much salt to add to your pool to reach your desired salinity. It can also calculate how much diluting water you need to use to lower the salt level if it is too high.

What Is The Ideal Salt Concentration In A Pool?

Generally speaking, salt water pools should have a salt concentration in the range of 2,700 - 3,400 ppm, with 3,200 ppm considered the ideal concentration.

Stay below this level for too long and your chlorinator will struggle to generate enough chlorine to adequately sanitise your pool.

Stay above this level for too long and you may see your chlorinator actually stop working, along with damage and corrosion of your pool equipment (filter, pump housing).

Check out this guide on how to test your salt level properly.

How Much Salt To Add To Pool?

As an example, if you have a 50,000 L pool with a current salt concentration of 2,500 ppm and you want to lift it to the recommended level of 3,200 ppm, you will need to add 35 kg of salt. This is about 2 x 20 kg bags.

The calculation goes like this. The difference between your desired concentration (3,200 ppm) and your current concentration (2,500 ppm) is 700 ppm. This is basically the same as 700 mg/L.

You have 50,000 L of water, so multiplying those two numbers together gives 35,000,000 mg. That's the same as 35 kg and it's how much salt to add to your pool.

How Much Salt Should I Add To A New Pool For Startup?

Typical mains water contains around 100-200 ppm of salinity, though this varies a bit depending on where you live in Australia. Bore water can contain up to 1,000 ppm of salinity.

If you have a 50,000 L pool filled with mains water (200 ppm salt) and want to lift it to 3,200 ppm of salt, you will need to add 150 kg of salt (7-8 bags).

Do this slowly, and definitely don't add the entire amount at once! Add a few bags, give it time to dissolve, then check the salinity with some salt test strips or a digital salinity meter (don't rely entirely on your salt cell's salinity reading).

Repeat this until you get to your desired salinity concentration.

Remember, it's a lot harder to get rid of salt than it is to add it, so make sure you don't overshoot and add too much! Also, make sure you turn off your chlorinator when adding salt.

How Much Water Should I Add To Dilute Salt Out Of My Pool?

If you do happen to add too much salt to your pool, the only way to get rid of it is to pump some water out of your pool (to waste), then refill it with fresh water.

The calculator will work out how much water you need to waste and subsequently refill into your pool. Simply enter a current salt concentration higher than your desired salt concentration to see this in action.

As an example, if you have a 50,000 L pool with a salt concentration of 3,700 ppm that you want to reduce to 3,400 ppm, you will need to pump out about 4,100 L to waste and refill it with fresh water.

That's a lot of water!

Summary

I hope you've found this metric pool salt calculator helpful when working out how much salt to add to your pool in Australia!

It can help you out when calculating how many bags of salt to add to your pool on startup, or when adding salt as part of routine maintenance.

If you've noticed any issues with this calculator or have any feedback, let me know over at the contact page!