How To Reduce the Salt Level In Your Pool

WRITTEN BY:  Inyo Pools

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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")


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EDS  Posted: 09/24/2016 23:30 PM 

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  Posted: 09/10/2016 18:02 PM  Inyo Product Specialist

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: 09/07/2016 20:18 PM 


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  Posted: 08/01/2016 12:15 PM  Inyo Product Specialist

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: 07/30/2016 15:19 PM 

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  Posted: 07/05/2016 12:32 PM  Inyo Product Specialist

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: 07/05/2016 10:38 AM 

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  Posted: 06/21/2016 12:06 PM  Inyo Product Specialist

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: 06/20/2016 13:06 PM 

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

Inyopools  Posted: 06/17/2016 16:04 PM  Inyo Product Specialist

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: 06/15/2016 19:26 PM 

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

Inypools  Posted: 06/06/2016 15:21 PM 

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: 06/05/2016 14:05 PM 

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  Posted: 06/02/2016 15:39 PM  Inyo Product Specialist

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: 05/31/2016 15:30 PM 

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  Posted: 12/22/2015 9:09 AM  Inyo Product Specialist

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 18:58 PM 

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  Posted: 12/07/2015 9:20 AM  Inyo Product Specialist

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: 12/04/2015 14:52 PM 

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  Posted: 12/04/2015 10:42 AM  Inyo Product Specialist

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.

GeneL  Posted: 12/03/2015 19:09 PM 

Is it true: for every one degree F rise in pool temperature above 77F, salt level will increase by 100ppm? e.g.: 77F, salt reads 3100ppm; 78F, salt reads 3200ppm, etc..Thanks.

Inyopools  Posted: 07/24/2015 9:50 AM  Inyo Product Specialist

jklon -Thank you for your feedback. We really appreciate your feedback.

jklon  Posted: 07/23/2015 14:18 PM 


Thank you so much for your help. The default was set for T-15. My cell was about to die. Replacing the cell fixed the problem and fortunately my salt was at 3400ppm "perfect". Thanks again!

Inyopools  Posted: 07/21/2015 12:35 PM  Inyo Product Specialist

Jklon - The diagnostics button procedure is associated with a Goldline Aqua Rite system. For an Aqua Logic PS4 system see "Cell Type" on page #14 of the Goldline AQL-PS4 Operation Manual. You select T-CELL-5 or T-CELL-15 (default) depending on which cell you have installed.

Jklon  Posted: 07/20/2015 14:58 PM 

I have a GOLDLINE controls - Aqua Logic AQ-LOGIC-PS-4 controls on my salt chlorinator. The diagnostics are menu driven and there isn't a diagnostics button. I'm looking through the manual and I am not finding any way to see the cell size.

Inyopools  Posted: 07/17/2015 21:32 PM  Inyo Product Specialist

Jklon - The stores usually have more accurate salt level measurements. Is there a local pool store that would give you a second store measurement? Also you have the largest cell size for a pool that is medium size. If you kept your pool chemicals balanced, your cell should have lasted longer than 3 years. Check to make sure that the cell size recorded in your control units matches your actual cell size. Push your diagnostic button 8 times to see the cell size. If you have a GLX-CELL-15-W, the display should read t-15. If not your system's salt calculations as displayed could be off.

Jklon  Posted: 07/15/2015 16:17 PM 

I have a GLX-CELL-15-W on a Hayward/Goldline Aquarite system. My pool is 15,800 gallons by the pool guy's calculations. I'm new to the house/pool but I discovered the cell is around 3 years old. My pool service guy cleaned the cell. He said it needed it. But my aquarite system before and after the cell cleaning is reading 2500ppm for salt and giving me a low salt indicator. But my pool service guy said I'm at 3900ppm. I went to a hardware store and got an indepent reading of 2900ppm who's right???? Is my cell bad? Do I lower the salt level or raise the salt level? Do I need to replace the cell (I already ordered one. Oh, by the way, my pool stays open year round.

Inyopools  Posted: 07/12/2015 11:47 AM  Inyo Product Specialist

Tam - These are rough numbers since I don't know what your actual salt level is. Your 16' pool with a 48" depth has about 6,000 gallons in it. Initially, when you were first adding salt to your pool to get it to a salt level of 3500 ppm (typical), you would have added 180# of salt (4 1/2 bags at 40# each). So at no time should you have more than 4 1/2 bags of salt in your pool. When you added 3 bags, I will assume you lost only 1/2 bag with the rain so you are ~2 1/2 bags over. Your pool should have 4 1/2 bags. It has 7 bags (assuming 1/2 bag lost). To get rid of 2 1/2 bags of salt you will have to dump 1/3 of your pool water (2.5 / 7) and fill with fresh.

Tam  Posted: 07/10/2015 19:57 PM 

I have a 16 inch round pool. We added 120 lbs of salt and after rain our pool is filled to top and high salt content is blinking! How much water do I need to remove?

Inyopools  Posted: 06/14/2015 17:49 PM  Inyo Product Specialist

Don - At 4800 ppm you are about 30% over the target salt level of 3400. To get down to 3400 you will have to replace 30% of your pool water with fresh water. If your pool has an average depth of 5.5' or 66", you will have to drain and refill about 20" of water [66'x30%] to get your salt level down to 3400 ppm.

Don  Posted: 06/12/2015 14:03 PM 

I have added to much salt for spring opening because I relied on reading on generator reading (like I had done for 12 years)but my pool store tested for 4800 and I need 3400 for Aqua Rite. 35000 gallon pool how much water will I have to draw down to get to correct level. I added 6 more bags than did last year, 4 bags more than year before.

Inyopools  Posted: 05/23/2015 13:57 PM  Inyo Product Specialist

Jaime - We usually recommend buying a SCG one size larger than your pool size requirement. However, your IC40 unit is way higher than that. It's sized for a 40,000 gallon pool. Even if you ran the unit at 20%, you would be producing chlorine for a 8,000 gallon pool. You could run it at 20% and turn the unit off every other day to get the average chlorine generated down to what is required for a 4000 gallon pool. Or you could buy a IC15 for a 15,000 gallon pool and run it at 20% with an occasional bump to 40% as required.

Jaime  Posted: 05/19/2015 21:13 PM 

We drained the pool and started fresh. The salt levels have been good so far. Now we are having issues with the Chlorine being too high. Our new pool service company said that our Salt generator is too big for our pool size. We have the IC40 and our pool is 3,800 gallons (very small). The pool service company shut the salt generator off about a month ago and the Chlorine levels are still high. Do you think we should have a smaller size salt generator like the IC15 or IC20?

Inyopools  Posted: 04/11/2015 0:41 AM  Inyo Product Specialist

Jaime - For a 3865 gallon pool you will need 112 lbs of salt to get your pool up to 3500 ppm.

Jaime  Posted: 04/10/2015 17:23 PM 

Thank you for your response. How much salt would you recommend adding to the pool now that we have drained it and added fresh water? The pool has approximately 3,865 gallons.

Inyopools  Posted: 04/08/2015 11:06 AM  Inyo Product Specialist

Jaime - I haven't heard anything about the acid fix either. Our only caution is to wait 10-14 days on a new plaster pool before adding salt to allow the plaster to cure. But you are way past that point. We usually recommend draining a small pool and starting over when the salt level is too high.

Jaime  Posted: 04/06/2015 17:31 PM 

We had a custom pool built in Sept 2014. It's 7 ft by 16 ft and approximately 3890 gallons.
We just found out our salt level are excessively high at 6400 and the calcium hardness is 1000.
We are getting different recommendations on how to resolve the issues. The builder of our pool recommends we have the plaster company come out and put acid the pool with some machine and let it sit for 10-12 days and then drain the pool and refill it. A pool cleaning company came out and told us that he wouldn't recommend the acid. He said that if we drain the pool and refill that he can maintain the salt levels. Thoughts??

Inyopools  Posted: 12/30/2014 15:16 PM  Inyo Product Specialist

High Salt Reading - Adding acid will not change your salt level. Heavy evaporation would but in this time of the year we tend to get rain which dilutes the pool water and lowers your salt level. Check the connections to your SCG control box to make sure they are tight. Then call the manufacturer. You may have to re-calibrate your system.

Anonymous  Posted: 12/29/2014 7:21 AM 

My salt water pool was built and filled in early September. I have been checking the chemistry on the pool every couple of days and add acid when the ph level is too high. No salt has been added to the pool since it was started up. Now my system says that the salt level is too high (4.1). How does the salt level rise without adding salt? Thanks

Anonymous  Posted: 08/04/2014 20:56 PM 

Make sure you are also keeping an eye on the converter. If it's turning white you need to pull it out and clean it as well as the copper pieces. this will help give you a more accurate reading.