How To Reduce the Salt Level In Your Pool

WRITTEN BY:  Inyo Pools

  3.94 out of 5 stars on 23 ratings
(Click on a star to add your rating)

You've just converted over to a salt water pool and discovered that your resulting salt level is too high. You were targeting for 3500 ppm and ended up with over 4000 ppm. How could this happen? The most common answer is you overestimated the size of your pool. Instead of having 13,000 gallons you have 10,000. Now you have too much salt in your water. How many pounds of salt are you over and how do you get that out of the pool water?

Step by Step


Step 1

The only way to reduce the salt level in your pool is to dilute it. And if your pool is full that means you are going to have to drain your pool down to a level that you can add fresh water to. You cannot wait for the water to evaporate. That does nothing to reduce the salt level. In fact, when the water evaporates, the salt still remains in the pool and your salt level actually goes up. So the question now is, "How much do you have to drain to make room for fresh water?".

Step 2

Salt water generators operate between values that range from 3000 ppm to 4000 ppm. We are assuming that you have a salt water generator that operates at 3500 and so you were adding salt to reach a salt level of 3500 ppm.

Step 3

When you measured your salt level using salt test strip you got a reading of just above 6.5 which equates to 4000 ppm. So you're over by 500 ppm. What's that mean in real numbers and how do you get it out of your pool.

Step 4

To help visualize this we will convert ppm to bags of salt. On the back of the salt bag it states that 1 40# bag of salt will raise the salt level by 480 ppm for a 10,000 gallon pool. So if your pool's salt level is 4000, you have just over 8 bags of salt in your pool (4000/480). To reach 3500 ppm in a 10,000 gallon pool you should have the equivalent of just over 7 bags (3500/480).

Step 5

You have about 8 bags of salt in your pool . You want to extract about 1 bag of salt. To do that you have to you have to drain about 1/8 of your pool water.

Step 6

When you replace that 1/8 of pool water with fresh water, you'll end up with 7 bags of salt or approximately 3500 ppm.

Step 7

So you must dump 1/8 of the pool's water. How many inches of water is that? First determine the average depth of your pool. If the shallow end is 3' and the deep end is 6', your average depth is 3' + 6' or 9 ' divided by 2 = 4.5'. This is equal to 54". To determine the number of inches to drain from your pool to dump 1/8 of your pool water, divide the average depth of your pool in inches by 8 (54 / 8 = 6.75 or approximately 7"). Bottomline - to reduce your salt water level from 4000 to 3500, you must drain out 7" of salt water and replace it with 7" of fresh water. The basic formulas you need to get to this number are restated below. They will work for any pool size.

Step 8

A: % OF SALT OVER TARGET PPM = (measured ppm - target ppm) / measured ppm. In our example (4000 - 3500)/ 4000 or 500 / 4000 = 12.5% which is the same as 1/8 discussed above. Note: It is not necessary to convert ppm to bags of salt as done above. That was only done to help visualize the problem. Also note that this formula works for most size pool. We only have to consider the depth , not the width or length.

Step 9

B: AVERAGE DEPTH OF POOL: (Shallow End + Deep End)/2 x 12. In our example, (3' + 6')/2 x 12" = 54".

Step 10

C: NUMBER OF INCHES TO DRAIN: B times A. In our example, 54" x 12.5% = 6.75" (approximately 7")


(1 to 40 of 90)

InyoPools  Posted: 10/1/2018 

Hello Michelle - Yes, you can set the valve to waste when you drain water.

Michelle  Posted: 10/1/2018 

Do you just set the valve to waste water to drop the salt level or do you have to vacuum?

InyoPools Product Specialist Dennis R.  Posted: 8/25/2017 

Rk - The only way to reduce your pool's salt level is to drain out some of the water and replace it with fresh water. I'd have a local pool store check your salt level to make sure your reading is accurate.

Rk  Posted: 8/24/2017 

Salt level is 3700 now. Can you lower the salinity percentage to decrease salt?

InyoPools Product Specialist Dennis R.  Posted: 7/20/2017 

Ronnie - I would have to know what Salt Chlorine Generation system you have to help isolate your salt level problem. From the partial readings, it sounds like your SCG is not producing chlorine. Generally, on many systems, when you change the cell, you have to enter the cell type into the control unit otherwise the unit will generate invalid numbers. If you have an Aqua Rite system, here is a link to "Haywards' Aqua Rite Diagnostics Manual". It may help you with general insights.

InyoPools Product Specialist Dennis R.  Posted: 7/19/2017 

Anonymous (high salt) - I need to know what SCG system you have to help you with HI salt level issue. Sounds like your SCG is not producing any chlorine. Even though the system is new, I'd have the cell checked. Throw in a bag of shock to control the algae while you are getting this resolved.

Anonymous  Posted: 7/17/2017 

We have a new pool that called for 4 bags and ever since it says high salt even drained half the pool and still high salt. Don't understand. We followed all the instructions. Pool just keeps turning green. Please help

Ronnie  Posted: 7/17/2017 

I will begin by saying I love the way you reply to customers with numerous questions, it made me want to trust you. My pool is 14000 gal. After 12 Yrs of used we had to buy a new cell, followed your steps to recalibrate it. Went through all steps to understand all the 9 codes and found out ours doesn't have 9 codes. Its always showing HI. Then I begin pushing the diagnostic button and this is what I get: Code #3 shows 0.00, so we don't know the cell amp. Code #5 indicates -0. Code #7 shows r-1.40 but not sure if is because the cell is T-15. Once I press to continue it goes back to HI and doesn't show any other codes, to my understanding our system has only 7 codes. Is still a bit green after following all the steps, we shocked it, pour murat ice acid, has a new filter, stabilizer, clarifier, you name it and let me know what else to do if I missed something. Thank you.

InyoPools Product Specialist Dennis R.  Posted: 7/10/2017 

LENA - I would question the results of the Clorox salt water tester. If you can, take a sample of your pool water into a local pool store. They have more accurate equipment and should test your pool water for free.

LENA  Posted: 7/8/2017 

Clorox salt water tester showed the salt to high at 7.0. I drained half the water out of my 12000 gallon pool.tested and the test shows the same.That can't be right.At my ropes end grrrr

InyoPools Product Specialist Dennis R.  Posted: 7/3/2017 

Anonymous (high salt level) - I would recheck your salt level. If your 53,000-gallon pool has a salt level of 9500 ppm, you would have had to put over 100 40 lb bags of salt into your pool. For a typical operating level of 3500 ppm you should only have about 39 bags in your pool. That would mean you would have to take about 60% of your water out and replace it with fresh water to get your salt level down to 3500 ppm.

Anonymous  Posted: 7/2/2017 

My pool is 53,000 gallons and the salt reader reads high in the 9 thousands how much do I need to drain my pool and clear up the water

InyoPools Product Specialist Dennis R.  Posted: 6/9/2017 

Anonymous (reduce salt) - All you really have to know is the amount of water you have to drain from the pool and the average depth of the pool as stated in steps 8, 9, and 10.

Anonymous  Posted: 6/8/2017 

Could you not just take (3500,Target/4000,current)=1/8. Then take 1/8th the gallons of pool water, (800 gallons) X 0.133681(gallons to Cubic Foot) divide by Length then divide by width. This will equal the number Feet to drain. Divide by 12 and you will have the number of inches to drain. The Salt bag is irrelevant.

InyoPools Product Specialist Dennis R.  Posted: 5/17/2017 

Chaphouse - You would, of course, have the auto fill off while you are draining the pool, but there's is no reason for not refilling the pool with the autofill unless it is too slow. If you drain below the skimmer and have diverter valves, you can shut off the skimmer and drain from the bottom of the pool to avoid getting air in the system. As for the algae problem, see our blog on "How to Clean a Green Pool". It's simple and works.

Chaphouse  Posted: 5/16/2017 

Thank you for all these comments! I found them very helpful!
I have high levels of salt in our pool, so now I will drain according to your directions. Should I turn off the auto fill and just re-fill it by hand. I guess I will also have to turn off the pump if I end up having to drain a lot of water, right?
Also, I have a bad algae problem since the salt cell isn't working. What should I do about that? I have put chlorine in twice now, and it is all gone, its like throwing it away...
Thank you again for your help!

InyoPools Product Specialist Dennis R.  Posted: 12/5/2016 

high salt level - See our guide on "How To Remove Calcium Scale Deposits From Your Pool Wall". Most people do not seal the tile after cleaning it. You will have less buildup if you maintain good chemical balance.

Anonymous  Posted: 12/3/2016 

Follow up question to the high salt level affecting the glass tiles---We have a pool service that checks the chemical composition of the water every week, but we still have the pitting and the heavy calcium build up. Based on the fact that the pool was maintained, do you have any idea what could be causing this? How would you recommend cleaning the tile and would you use a sealer after the cleaning? thanks!

InyoPools Product Specialist Dennis R.  Posted: 11/4/2016 

high salt level - High salt levels should not affect the glass tiles, but you do increase the risk of metal corrosion in your pool system. If the rest of you chemical levels have also been ignored for a year, you can have pitting in the pool walls and a white calcium buildup on the glass tiles.

Anonymous  Posted: 11/3/2016 

What happens to a pool with glass tile around the water line and perimeter spa when the salt level is high, around 5000 ppm, and has been for a year? What changes would I see? Would there be any damage? Thanks

EDS  Posted: 9/24/2016 

I'm glad I found your web site. I added to much salt to my 15000 gallon pool because I did not realize my T-cell was going bad. After buying a new cell it would not work with such high salt level. With your calculations I drained 22 inches out of the pool. I added fresh water and now good to go! Thanks

InyoPools Product Specialist Dennis R.  Posted: 9/10/2016 

jcatespool - Not sure which Salt Chlorine Generator you have but if it's close to a Aqua Rite, here's a helpful guide - Hayward's Aqua Rite Diagnostics Manual - that may help solve some of your current or future problems. Also if your pool's water flow drops to almost nothing, check for a clogged pump impeller - How To Clean Out a Pool Pump Impeller. It's a common problem. Good luck to you!

jcatespool  Posted: 9/7/2016 


Thanks for all the comments and recommendations. You info here, I think, has hopefully saved me some money and a lot of "scratching my head".
While reading comments by Jklon and you, I realized the diagnostic reading display shows t-3 on my board, however, the cell that is installed on my system is a t-15. I am in the process of learning to care for and test our pool after paying someone to do a less than adequate job for at least the last year. During my "learning curve" of taking over these duties myself, the booster pump for our Polaris sweeper went out, and Hurricane Hermine came and went, taking out our electricity for about 36 hrs. Trying to clean debris, test chemicals, and access what to do to reach desired levels, especially Cl, I realized something was amiss. Our control panel was set for a t-3 rather than a t-15, thanks to the no-longer-employed-by-me pool guy, who replaced the board (probably unnecessarily) just before I asked him to no longer tend my pool.
Hopefully, I have dodged a bullet to the check book by noticing this while trying feverishly to figure out why my SCG read "low salt", then salt was added, and then immediately getting a "high salt" indicator!

Thanks again, and especially for allowing me to vent my frustration here, as I believe, after allowing the pool to cycle a while, I feel sure my readings will be accurate.

InyoPools Product Specialist Dennis R.  Posted: 8/1/2016 

mickster - You can't do this piecemeal by doing a series of drains because you are draining some of the new fresh water each time you partially drain the pool. Figure out how much you are over your desired salt level and drain the pool once according to that number. Example - If your salt level is 4500 and your desired salt level is 3500, you are over by 1000ppm. Roughly, every 1" of water drained will reduce your salt level by 75 ppm. So to reduce your salt level by 1000ppm, you would have to drain 13" of water from your pool (1000/ 75).

mickster  Posted: 7/30/2016 

I added too much salt to my pool before I found out it was my salt cell that went out. I keep draining the pool and adding fresh water but the level doesn't seem to going down. The salt level is still high?????

InyoPools Product Specialist Dennis R.  Posted: 7/5/2016 

AngieW - Yes, most Salt Chlorine Generators shut off when the salt level is too high. Higher salt levels cause the SCGs to work harder, using higher amperage and overheating.

AngieW  Posted: 7/5/2016 

We had a Salt System put in (AutoPilot Digital Nano) two months ago and have had nothing but issues. I'm pretty sure our cell isn't working. I get 0 for chlorine most of the time. We just came home from vacation and there was alge on the bottom of the pool, and I have a pool service! I have started taking my water to the pool store for testing and my salt was over 5000 I drained about 7 inches and got it down to 4400. I'm draining again trying to get it to 3400. My pool store says that salt systems won't make chlorine if your salt is too high. Is this true? Once I get it to 3400 I'm going to see if I get good chlorine reads through the week.

InyoPools Product Specialist Dennis R.  Posted: 6/21/2016 

Robyn z - If you have a "Waste" setting on your filter's multiport valve, you could use that. The water goes from the pump directly out the Waste port. If you use "Backwash" for a period of time, you will be dumping some of your sand with the water.

Robyn z  Posted: 6/20/2016 

Can you drain the pool through the backwash setting on the pump? Or should you use the regular drain??

InyoPools Product Specialist Dennis R.  Posted: 6/17/2016 

Debbie - I would definitely run the pool pump to mix the fresh water with the existing water. I'd wait to turn on the chlorinator till after the water is mixed.

Debbie  Posted: 6/15/2016 

After you have drained the pool, should the pool and chlorinator be running while you add the fresh water during this process?

Inypools  Posted: 6/6/2016 

lahunter - High levels of salt like 7900 aren't good for the SCG or the pool system in general. The SCG uses higher amps to convert the high salt content to chlorine causing the unit to overheat and deteriorate faster. You should dump 1/2 of your pool water and refill it with fresh to get the salt level down to just under 4000 ppm. As a rule of thumb, each inch of water drained will reduce the salt level 100ppm. Your desired chlorine output should be set at the level you had before you increased the salt level.

lahunter  Posted: 6/5/2016 

Our salt water generator was showing sal
t extremely low at 1900.we added way too much salt and it is now reading 7900. Will this high salt level damage any of the pool equipment? Also, were should dial the salt generator setting percent level control?

Thanks, Richard

InyoPools Product Specialist Dennis R.  Posted: 6/2/2016 

john - If your SCG is not generating chlorine, the fact that the salt is not being converted to chlorine would not increase your salt level. 3500 ppm is close to the upper limit on the acceptable salt level for most SCGs. If your SCG is sensing 4000, it may have shut down. Try replacing 3 " of your pool water with fresh water to get the salt level down. Also, make sure your cell is clean. That can cause inaccurate readings. I would guess the "45% chlorinator" display would be the level of chlorination that you set your SCG to.

john  Posted: 5/31/2016 

Hello - I recently saw a spike in the salt levels in my pool. We have not added salt to it at all and the level is normal (automatic leveler). The display was reading as high as 4000 but the pool store tested it at 3500. All of my other levels were fine - except that there was 0 chlorine. My question is, if the salt cell stopped working, and the chloride is not being converted to chlorine, would that show an increase in my salt levels? OR because my salt levels are so high, did the salt cell shut down? The screen also reads 45% chlorinator - which I have no idea what that means. Any suggestions?

InyoPools Product Specialist Dennis R.  Posted: 12/22/2015 

GeneL - Good question. I have been told by several SCG manufacturers that the sodium and chloride do recombine back to salt; that the only way your pool's salt level is reduced is by adding fresh water due to draining and splashing. Ask that question again in a year and see if the answer is the same.

GeneL  Posted: 12/17/2015 

If the salt cell breaks down the salt into it elements releasing separated chlorine and sodium into the pool water, over time, does this chemical reaction reduce salt levels? Or does the sodium and the chloride eventually re-combine? Can you tell that I flunked chemistry?

InyoPools Product Specialist Dennis R.  Posted: 12/7/2015 

GeneL - You are correct. Adding fresh water to bring your pool up the original water level will bring your salt level back down to its original ppm before evaporation.

GeneL  Posted: 12/4/2015 

OK, thanks. And because I have a fresh water auto-fill, evaporation will be replaced with fresh water and is not going to change the salt level.

InyoPools Product Specialist Dennis R.  Posted: 12/4/2015 

GeneL - No. Salt level does not increase just by a rise in pool temperature unless you consider evaporation. When pool temperature rises you will have more water evaporate which will increase the salt concentration in ppm but not to a fixed formula like you asked about.