How to Lower your pool’s salt levels

Do you have a brand new salt water chlorinator and you went overboard with adding the salt? Or is the pool water tasting saltier than normal? Need to lower your pool’s salt levels? You’re at the right place! Today we’ll share some practical tips on how to effectively lower your pool’s salt levels.

One of the reasons why salt water chlorinators are so convenient is that their fuel (yes, I don’t have a better word for it) stays in the pool after it does its job. See, a salt water chlorinator takes the salt, breaks them down into its components which are sodium and chlorine, the chlorine goes and sanitises your pool water then re-binds with the sodium, reforming into salt and the cycle begins anew.

Salt doesn’t evaporate or degrade over time and the only way to lower your salt levels is to take out the excess water and refill with new water to dilute whatever is left. To know more about the difference between a salt water pool and chlorine pool, click here.

First Step to Lowering your pool’s salt levels

Many experts will say that testing the pool water is the first step to lowering the salt levels in your pool, but here, we recommend topping up your pool water first to its recommended levels before testing. The only way to get proper readings for salt levels is to get a reading with your water levels at the pool’s rated capacity. This way you’ll have a good baseline to get your pool’s true salt readings.

Once you’ve topped off your pool water to its optimal levels, allow your pump to run for one whole cycle or a day to make sure that everything is properly circulated. Once that’s done, then you can proceed with testing the pool water with some salt water testing strips. Sometimes all that’s needed is a fresh water top-up!

While some salt water chlorinators have some built-in indicators for salt levels, if you really want to get an accurate level then test strips are the way to go. Your chlorinator readings can be skewed by a number of things like dirty salt water cells, damaged leads and so on.

The proper way to test your water is to get a small plastic container and fill it with some pool water taken at least a hand’s depth from your pool surface. Pour the excess away and leave just a little bit so that the bottom of your testing strip can stay submerged. Place the container on a stable surface and place the testing strip (bottom first) inside the cup. Only the bottom part should be touching the water. The whole process usually takes around five minutes so be patient. Once the test is complete, compare the results with the included chart and you should now have your pool’s true salt PPM levels.

What’s the right PPM level for your pool?

The answer for that will actually depend on your salt water chlorinator. For example, the Water TechniX Atomic Salt Water Chlorinator can function properly with salt levels at the 2,500 to 3,500 PPM levels. So it’s best to consult with your chlorinator’s manual to determine what the right salt levels are and to see if there’s a need to lower them.

Get your Water Volume / Measure your pool

If you already have your pool water volume written down somewhere then great! No need to measure your pool. But if you’ve forgotten it (or if you don’t have it handy) we have a great guide on how to measure your pool here. (Don’t worry, clicking it will open a new window) The post also contains a handy pool water volume calculator so all you need to do is to take the measurements and the calculator will do all the math for you! Once you get your pool’s total volume then we can move on with lowering your pool’s salt levels.

Computing how much water we need to take out

Once we have your pool’s total water volume and the actual salt reading then we can go ahead with calculating how much water we’ll need to take out to effectively reduce the salt levels to their recommended levels. As an example, let’s just say that you have 4,500 PPM of salt currently in your pool and you have a 40,000 L pool.

*Note: If your pool’s salt water concentration is just a couple of hundred PPM higher than the recommended levels, then it’s okay to leave it, but for values 500PPM or more from the recommended levels then partially draining is the way to go.

Step One: Divide your current reading by the recommended salt water concentration. For this example, the recommended level is 2,500 to 3,500 so let’s just get the high end of the recommended level, 3,500.

4,500 PPM (current reading) / 3,500 PPM (recommended level) = 1.29 (rounded up)

We want this number as close to 1 as possible, so we take the value above 1, in this case .29 and we multiply it with our pool’s volume.

.29 x 40,000L = 11,600L

This means that in order to reduce the PPM of our water down to its recommended level, we have to drain out 11,600L of water and replace it with fresh water.

Partially Draining Your Pool Water

While you can use your pool pump to drain out the water by setting your sand filter to the waste position or using the drain valve if using a cartridge filter, we don’t really recommend it for draining large amounts of water that will cause your water levels to drop below the skimmer levels as this can cause your pump to lose prime and/or burn out when it runs dry. You can either get a small submersible pump to do this (which costs about a few hundred bucks) or use our favorite tool when it comes to draining water, a venturi pump. (That is, if you don't know anyone with a spare helicopter and a thousand litre bucket lying around)

A venturi pump doesn’t use your pool’s pump, instead it uses regular water pressure from your garden hose so it’s a very efficient way to drain your pool if you ever need to lower your water levels for any reason. A venturi pump can remove an average of 3,025 to 3,400 litres of water per hour. So using the example above, we’ll need to use the Venturi pump for roughly 3-and-a-half hours to effectively drain around 11,600L of water from our pool.

Refilling and Retesting

Once we’ve drained out enough water from our pool, we should then refill it with fresh water. Once that’s done, allow your pump to recirculate the water for one whole cycle or at least a day to make sure that the water is fully diluted before testing again.

If you followed all of the steps outlined above, then your pool’s salt concentrations should be at the approximate levels needed for proper chlorinator efficiency. Again, don’t worry if it’s a few hundred PPM shy of the mark, that’s fine by all standards. If you’ve overshot and your levels are lower than the recommended levels then adding salt should be easy enough. Remember, for every 10,000 L of water, 10kg of salt adds 1,000 PPM.

Note: Don’t forget to check your pool’s chemical levels as well! You’ve effectively removed part of ALL your pool chemicals along with the salt that you’ve taken out, so retest and rebalance accordingly as well! For more information on pool chemical levels and resting, check out Mr Pool Man's Ultimate Guide to Pool Chemicals and Mr Pool Man's Ultimate Guide to Testing your Pool Water.

Do you have any questions about this topic or the featured products? No worries, we're here to help! Drop us a question down below and we'll get back to you ASAP.

Happy swimming :)

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