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

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 22 of 22)

Add Comment

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".


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?

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


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?


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.

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......


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?

Back To Top

Please Note:

Inyo Pool Products is not responsible for any injury or damaged equipment
while using our guides. Using our guides is doing so at your own risk.
These guides are suggested use of your pool or spa equipment and may vary
depending on which product you are using.