How To Reduce the Salt Level In Your Pool

Written by:  Danny Rhodehamel

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?

Tips & Warnings

Things You'll Need

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")

Comments (1 to 40 of 55)

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User: Inyopools

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.

User: GeneL

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?

User: Inyopools

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.

User: GeneL

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.

User: Inyopools

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.

User: GeneL

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.

User: Inyopools

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

User: jklon


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!

User: Inyopools

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.

User: Jklon

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.

User: Inyopools

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.

User: Jklon

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.

User: Inyopools

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.

User: Tam

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?

User: Inyopools

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.

User: Don

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.

User: Inyopools

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.

User: Jaime

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?

User: Inyopools

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

User: Jaime

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.

User: Inyopools

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.

User: Jaime

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??

User: Inyopools

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.


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


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.

User: Inyopools

High salt level - The only way to reduce your pool's salt level is to drain water from the pool and add fresh water like you did. Not sure why you got high salt readings after dumping half your pool's water. That should have dropped the salt level to half of what it was. Either your salt level was way off - like 8000 ppm or your salt readings are off. I would take a sample of your pool water to your local pool store and have them test it. As to the extra bag of salt - you are probably going to have to dump more water and add fresh again.


I have drained half of my pool and added fresh water still says high salt I bought 40# pounds and my husband put it in and it didn't need salt but he thought because I bought it needed it please help get salt level down

User: Inyopools

briel - While alkalinity can affect the pH level, the two are not the same and are adjusted by two totally different chemicals.See our guide on " How To Maintain A Swimming Pool Part 1 (Chemicals)" On your salt level, you can have high salt levels without generating chlorine. That's all in your SCG setting. Try turning your SCG off instead of 20% until your chlorine level is down. Have your pool company measure your salt level. If it is way too high, you will have to dump a lot of your pool water and replace it with fresh. Re-read this guide. You may have to dump 1/8 of your water or more if your salt level is really high.

User: briel

I have a 25,000 gallon saltwater pool at the house I just moved into last summer. The pool was already "up and running" last year when I moved in, so I didn't have to mess with starting it up correctly. Therefore, I am still learning how to start and maintain everything correctly. (I kind of know what I'm doing, and I research a lot).

First of all, the TA was WAY too high, and the PH was 8.0. I used less muratic acid than recommended, but the TA is still almost double what it should be, and PH is now at 7.2. How can I lower the TA without lowering PH? I've read that sodium bicarbonate raises both. What about sodium carbonate/soda ash though? -If I use this, will it also raise the TA? What is sodium tetra borate then?

Second, the light on the salt-water cell has been showing "high salt" for several weeks. Also, the chlorine is at 16ppm. (I took some bad advice from the previous pool store that I was using and put in way too much chlorine). Anyway, no one has used the pool yet this season. I realize that bathers would help lower chlorine levels, but I just simply do not have the time right now, and I don't want the high chlorine level to damage anything. -How does the salt affect chlorine then (or vice-versa)? I have the cell set to 20% output, and I haven't shocked it in over 2 weeks due to the high chlorine level. I have backwashed (for almost 5 minutes each time) 3 times in the last 2 weeks, and then added new water. I thought this might help, but the chlorine hardly dropped.

Any advice would be appreciated. If you are not certain that the information or advice you are providing is accurate, please leave it to the experts. :) (I've already spent a lot of money).


User: Inyopools

Mariel - Salt concentration can go up with evaporation, but I am guessing that you are refilling you pool with fresh water so that is probably not the problem. You PC board may be going bad. I would suggest calling Goldline at this number, 888-921-POOL. Their tech staff would have an accurate answer to your problem.


Thanks for your great posts. I am a first time pool owner and I am amazed at the cavalier attitude of both the previous owners, the pool store folks and the guy I paid to give me a tutorial about my pool. This is equipment needs to be treated with care and proper instructions. But I guess most places are only too happy to replace things broken by pool owners. sigh..

Question: If my my Aquarite system has been fine (t15 only a year old) and salt levels running around 3200 for all last fall and winter, why would it jump to 3900 ( 4100 at pool store) if no salt has been added in at least 10 months? I took the cell in for a check and they said it was fine. I clean it as per the directions

I have a brand new Aquarite due to an electrical storm last October. But all of a sudden this past month the salt level has just been creeping up. Other numbers are:

Calcum 390
CYA 40
TA 100

pH and PO fine.

Thanks for your professional advice.

User: Inyopools

Ken - Variation in test results is a common problem. All I can offer is to make sure your test strips are stored properly and aren't too old. And try to find a reliable pool store. Take a pool sample in a couple of times within the week to the same store. If the results are drastically different, ask why.

User: ken

I feel compelled to share my situation with the group: I just had a 20,000 gallon pool installed, and had been balancing the water and adding salt by checking levels using test strips. After putting in the minimum required amount of salt for my pool, test strip reading said I was at only 1800 ppm salt. I added two more buckets and I was only at 2000 ppm. Skeptical, I brought samples to 2 different pool places for analysis. Store A gave me results of 3900 ppm salt. Store B gave me result of 3600 ppm. system at home reads 3500 ppm. Moreover, I have seen DRASTIC differences in Ph, alkalinity, and cyanuric acid levels between the two water tests and my own test strips, all 3 give me different results, some in range, some out. Note that the water has been crystal clear and that, since the system says 3500 ppm, I have turned on the chlorine generator. All I want is a reliable test result so I can balance evrything to the correct levels!! I do not trust test strips and wonder if the tests at stores are done by capable personnel or calibrated machines. Is anybody else wondering this? is there a reliable test method/system that I can use on my own to accurately keep my levels intact?

User: Inyopools

Debi - I would take a sample of your pool's water to a local pool store and have them check it for salt. Most stores do this for free. If it reads high like your system is showing, you are going to have to dump more than a couple of inches of water and add new fresh water. See this guide to calculate amount. If the store reading is within limits, you may have to replace a PC board in your system.

User: Debi

Our salt was low and the pool was green a couple of weeks ago. We put in 3 bags of salt and after 2 days it reads 7500. I drained out a couple of inches of water but no change. Do we keep draining, it's a vinyl liner pool. It is super clear. Could the box be wrong, it isn't even a year old. Thanks

User: Inyopools

crpittman - You can add salt as soon as your pool is in balance chemically. Remember to turn off the salt chlorine generator until the salt is completely dissolved - about 12-24 hours.

User: crpittman

We just put in our first salt generator. One pool place said we could not add salt till 2 weeks after we added the calcium. Another said you could add salt as soon as the pool was in balance chemically. Which is correct?

User: Inyopools

Jim - Yes, when you add salt, you should turn off your salt chlorine generator and run your pump until the salt is completely dissolved - can be 24 hours. Here's our guide for "How To Add Salt To Your Pool".

User: Jim

What is the best procedure to add salt to my pool. The reading at the store was 2700, pretty close to what I read; They said I should add a 40# bag. I have added salt in the past, but I have heard of various methods of adding salt. Like turning off the genator and running the pool motor for 24 hours before turning it back on? What do you recemmend?

User: eventnyc

My pool was contaminated by salt water due to Hurricane Sandy. I finally got it nice and clean; however, I foolishly added 1 40 lb bag of salt. My salt level was up to 4400. I just managed to get it down to 4000 after taking out and emptying several inches several times. I stuck at this level and it doesn't seem to want to come down lower. I keep trying to add fresh water. Is there another way and how long do you think this may take? My salt chlorinater is not going on. Am I doing damage to the brand new chlorinater?

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