How To Reduce the Salt Level In Your Pool

Written by:  Danny Rhodehamel
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 (4.17 OUT OF 5 STARS ON 15 RATINGS)

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

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 30 of 30)

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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.

User: 

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).

THANK YOU!!

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.

User: 

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?

User: Inyopools

drain water from pool - I would cut in a 1 1/2' ball valve and waste line into the pressure side of your pool system. See on guide on "Adding a Pool Waste Line".

User: 

I need to drain excess water from the salt water system. What is the best piece of equipment to handle this? Do I need a special pump to handle the salt water?
Fran

User: Inyopools

water logged - Changing over to a salt system does not change your requirement for a filter system. And any filter system, sand, cartridge or DE, can be used with a salt system

User: water logged

do you need a sand filter with a salt system

User: 

Just want to say thanks. I searched "how to reduce salt level in pool" and found this post. You've already answered all my questions and just wanted to say thank you for taking time to help others.
Sincere regards

User: InyoPools

High Salt Usage - You are using way too much salt. Salt Chlorine Generator users typically add up to 1 bag of salt at the beginning of the season and that's it. Take a water sample into a pool store and have them check it. Your own readings may be off. The only other explanation I can think of is that you have a major leak and are continually adding water and diluting you salt level?

User: 

Hi I have a 15000 gallon pool that is taking a 40lb bag of salt every 2 weeks! Any ideas why it is using so much salt?
Generator is at 40% and producing good chlorine levels.
Thanks
Mark

User: Dick

Thanks for responding. I have learned a very important lessen. Don't rely on indications from your salt generator, test your salt level and add as needed. It's a lot easier to add salt than remove it.

User: InyoPools

Dick - I don't believe that salt "settles" out and down once it is dissolved, so I would think the salt density is the same throughout your pool. It should not matter if the water comes out of the top or the bottom.

User: Dick

My salt generator indicated I needed to add salt, before I realized my mistake I had added way to much salt. The salt generator was defective and I had not taken a salt level reading ( my mistake). My salt generator cell is on its last leg, I have purchased a new complete system, but I am trying to hold off on installing the new system until I get the salt level down. Are salt levels higher at the top or bottom of the pool? The reason I ask, should I drain as much as possible through the skimmer or is it better to drain from the bottom drains?

User: mcleod

Thanks a bunch, didn't know what to do? This helps a lot......

User: 

This info was really helpful, thanks guys

User: LittleShaggy

I was looking for this. Thanks for the information

User: Jeanette

My cell was out in my pool and we keep adding salt, beacause we did not know the cell was out and pool was turning green. Then we bought a new cell and it cleared up overnight. Our salt level was 5000, so we had to keep back washing and add new water each day. The cells only last about three years for salt water pools make sure you keep the warrenty.

User: Paula Parker

Our pool is 20'x40' we had the salt tested and it read 7000, OMG! Presently, I am backwashing pool down a couple of feet and adding water, I will do this each day and test my salt until it is right, also I am adding chlorine each day since my 'cell' is not working..... Does that sound right?

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