Water Chemistry For Saltwater Pools

Charlie Ramirez

October 23, 2024

5 Minute Read

– BLOG UPDATED 9/25/17

Some pool owners have a misconception that throwing shock into the pool and owning a salt chlorine generator forfeits you from having to deal with chemicals again. Unfortunately, this is not the case. Yes, you will worry less about certain chemicals, but the importance of a well-balanced pool remains.

Before attempting to operate your new saltwater chlorine generator, there are a few steps every pool owner should follow to ensure the best use of your system. Did you know that before you even operate your unit, salt must be added to your pool? Actually, you should evaluate your pool’s water chemistry as a whole. A properly balanced pool is not only essential to the performance of your chlorine generator but also important in protecting your pool equipment and swimmers from other potentially dangerous situations.

To help out new salt chlorine generator owners, we’ve created a chemical quick start guide before operating your chlorine generator.

STEP 1: Calculate Pool Volume

Poolvolumecalc

One of the first things you should become very familiar with is how many gallons of water your pool holds. This information is used frequently when trying to size your equipment correctly for your pool and when you’re adjusting chemical levels.

You can determine the number of gallons of water in your pool by using the formulas to the left. For non-standard shaped pools, it may be easier to break your pool into sections to calculate. Then, simply add all the sections for a total amount.

STEP 2: Adjust Your Salt Levels

Before you do any adjusting to your salt levels, you first have to determine how much salt is currently in the water. We offer various pool water testing equipment on our site that you can purchase that will assist you in testing your water. The recommended salt levels are between 2700-3400 parts per million (ppm), with the ideal level being at 3200 ppm. (Some systems may require a higher minimum level. Check your manual for specifics)

After testing the salt, determine how much you need to add until you reach the 3200 ppm mark.

Salt chlorine generators may indicate low salt sometimes and it prompts pool owners to add more salt. Then, once they test their levels, their salt PPM is extremely high. The reason this happens is due to a failure in the salt cell. Failure in your salt cell can trigger false readings. To ensure proper levels, always, always, always test your pool water. A simple water test can tell you where your pool water stands as a whole allowing you to make adjustments accordingly.

STEP 3: Adjust Cyanuric Acid

Cyanuric acid (stabilizer) is essential to the performance of your chlorine generator system. Cyanuric acid is a mild acid that helps prevent the breakdown of chlorine due to the sun’s ultraviolet rays. If you live in a region where the sun is a frequent visitor, you may want to pay close attention to these levels. For cyanuric acid, the ideal level for outdoor pools is 60-80 ppm, while for covered pools it is 20-40 ppm. The ppm for indoor pools should be 0, as there is no need to add stabilizer to a pool not affected by the sun.

STEP 4: Adjust Free Chlorine

You should test and monitor your available free chlorine levels on a weekly basis. Free chlorine levels should remain between 1-3 ppm. You can lower your free chlorine by reducing the output setting on your generator. Also, consider increasing the pump runtime if you cannot maintain a high enough FC.

STEP 5: Adjust Total Alkalinity

The total alkalinity (TA) measures the total alkaline substance in your pool water. Alkalinity is the name given to the capacity of an aqueous solution to neutralize an acid. The ideal level for TA is 60-80 ppm. The results of improper TA levels range from corrosion of metal pool parts, staining of your pool, burning and itchy eyes, cloudy water, and reduced chlorine efficiency. You can increase the pool‘s TA using sodium bicarbonate (baking soda) and decrease the TA using muriatic acid

STEP 6: Adjust Calcium Hardness

Calcium hardness is the measurement of the total amount of minerals that are found in your pool’s water. If you’ve heard the phrase ‘hard water’, it is simply referring to a high mineral content. Ideally, your total hardness should fall between 200-400 ppm, however, it may vary if you have a fiberglass or vinyl pool. Too much calcium hardness causes scaling in your pool and too little causes your pool water to become corrosive. While drinking ‘hard’ water is not necessarily harmful to one’s health, it can pose serious problems to your pool equipment.

50-300 ppm for vinyl (Do Not Add)
220-320 ppm for fiberglass
350-450 ppm for plaster

STEP 7: Adjust pH

pH is the measure of how acid/alkaline the pool water is. Pools with a pH of less than 7 are considered acidic. The ideal pH level for your pool is 7.2-7.8. If your pH is too low, the water can become corrosive to your pool equipment. If your pH is too high, the chlorine becomes much less effective for sanitation. Pools with salt systems tend to have a higher pH level. Because of this, you will probably be adding a little more acid to your pool than most traditional chlorine pools. If you don’t keep your pH levels in check and they continue to rise, calcium scaling along your tile walls begin to develop. Additionally, calcium scaling also affects your saltwater cell, thus shortening the overall lifespan of the cell itself.

Water chemistry for saltwater pools slightly varies from traditional chlorine pools. If you need advice on balancing your saltwater pool, post your results in the comments section and we’ll do our best to help you get your pool balanced.

Troubleshooting Topics

Controls / Automation

Chlorinators

Skimmers / Drains

Need Replacement Parts?

Swimming Pool Products

89 responses to “Water Chemistry For Saltwater Pools”

WhyMeLord

August 19, 2015

I’m a retired engineer (EE) with a fair amount of process control experience. I know the industrial process & hardware but haven’t found much in the way of information on the hardware and software for monitoring the small scale processes involved in a residential pool. Any information on sources would be appreciated.

Reply
1. Matthew Simmons
  
  August 25, 2015
  
  To help point you in the right direction, what specific processes are you interested in measuring?
  
  Reply
  1. Kathleen Whitt
    
    August 19, 2020
    
    I set up my above ground pool 1 week ago. It holds 14,000 gallons. I added 320# salt, ran filter 24 hours, then chlorinated 8 hours daily. I could never get measurable chlorine levels. I ran boost for 24 hours and now it says low salt. All levels tested are off.
    
    Reply
    1. Matthew Simmons
      
      August 20, 2020
      
      When installing a new salt system, I always like to throw in a bag of shock to give the generator a helping hand. The shock kills anything that may be lingering in your water while allowing the generator a chance to build chlorine levels. By the time the shock has worn off, the chlorinator should have a solid foundation of chlorine to keep your pool happy.
      
      Reply
Trish

April 23, 2017

Electronic NaCl monitors actually measure TDS, so if you have hard water an electronic monitor will not give accurate results – is the same true of measuring salt levels using dip sticks? I want to know the best way to measure my salt levels in my salt pool, in an area where the water has about 470-500 ppm.

Reply
1. Matthew Simmons
  
  April 26, 2017
  
  You can buy electronic handheld salt testers, or you can take a sample to your local pool store for free tests.
  
  Reply
Heather

May 15, 2017

I have the intex 16x 48″ pool ultra. It can with the pump salt generator and filter. I am wanting to upgrade the filter because it seems I am always changing it. I cannot ever keep my chemical levels steady. I also have many questions about which chemicals are best to use. I see that there are algecides and shock just for saltwater but my pool company sells me shock that says nothing about being for “saltwater pools”. Are there certain things that need to be for saltwater while others work for all?

Reply
1. Matthew Simmons
  
  May 16, 2017
  
  There may be “saltwater shocks” on the market, but most pool owners use the standard cal-hypo and it work just fine. If you want to learn about water chemistry, read this guide: Water Chemistry For Saltwater Pools
  
  Reply
RCook

June 27, 2017

Charlie, this was a very informative and well-written article. Kudos sir!

Thanks,

Bob Cook
Montgomery, TX

Reply
Pat

July 22, 2017

My salt water levels are high 3700 for a 16 x 48 pool but my salt water filter light remains on. Thoughts?

Reply
1. Matthew Simmons
  
  August 2, 2017
  
  The 3700 ppm reading you are getting, is it on a home test kit or from a pool store?
  
  Have you tried cleaning the cell? Also, how old is the cell?
  
  Reply
Pat

July 22, 2017

Sorry meant to say my low salt filter light remains on.

Reply
Jack

September 1, 2017

I’ve read this a couple of times, but where is the recommended ppm of Chlorine?

Reply
1. Matthew Simmons
  
  September 1, 2017
  
  The Free Chlorine level should be 1-3 ppm.
  
  Reply
Alan L.

October 17, 2017

Charlie,

Great article! Thanks! Is there any information or data to suggest that a by-product of a salt water chlorination is barium? We recently had a comprehensive water analysis conducted on both our home drinking supply and our salt water pool. While there was no barium detected in the potable water, barium was detected in the outdoor pool. While the barium levels were well within the federal drinking water standards, we were surprised at this discovery. Thoughts?

Reply
Alan L

October 17, 2017

Charlie,

Is there any information or data to suggest that a by-product of a salt water chlorination is barium? We recently had a comprehensive water analysis conducted on both our home drinking supply and our salt water pool. While there was no barium detected in the potable water, barium was detected in the outdoor pool. While the barium levels were well within the federal drinking water standards, we were surprised at this discovery. Thoughts?

Reply
Alan L

October 17, 2017

Charlie,

Is there any information or data to suggest that a by-product of a salt water chlorination is barium? We recently had a comprehensive water analysis conducted on both our home drinking water supply and our salt water pool. While there was no barium detected in the potable water, barium was detected in the outdoor pool. While the barium levels in the pool were well within the federal drinking water standards, we were surprised at this discovery. Thoughts?

Reply
Jerry

February 19, 2018

I just replastered my pool with a pebble tech finish, and installed a salt system. The start up pool guy raised the cyanuric acid level to 100 ppm. The local pool store tested the water and suggested I jshould drain some water out before adding the salt. Your thoughts?
Jerry

Reply
1. Matthew Simmons
  
  February 22, 2018
  
  How long did you wait after to convert to salt after replastering the pool? Hopefully, it was at least 30 days after the replaster.
  
  Here is the start-up procedure for the Pebbletech.
  
  Reply
Ron

March 3, 2018

I have vinyl salt water pool (around 75M3) with a Astralpool Sel Clear 95 chlorinator. Also I have a cover over the pool during winter. In the summer when the cover is opened I adjust the chlorinator to 90% of its capacity but I suffer from dropping PH levels. I have tried everything but I can’t find a solution to prevent the PH dropping. Once dropped I add PH+ to correct the levels and add some chloride tablets (4/5 tablets). That keep it sort of stable but after a day or so, the PH drops again, Check the salt level (5.1pps) but it is all fine.
You have any idea whats wrong? I get so frustrated but perhaps you have some good leads..
Thanks
Ron (from Spain)

Reply
1. Matthew Simmons
  
  March 5, 2018
  
  That’s a mystery to me because salt pools usually run high in the pH category. But my best guess would be that the added tablets are causing the issue. Tablet chlorine also contains stabilizer which will lower your pH. So you may get your pH where you want it after adding the pH+ but then you add tablets, give them a day to start to dissolve and the stabilizer has a chance to lower the pH again.
  
  If the salt system is working properly it should not require tablets. If you need a quick dose of chlorine, add shock or liquid bleach.
  
  Reply
2. MynameisJEFFFFFF
  
  July 25, 2018
  
  Check your total alkalinity is correct. it will mess up the reading on the PH probe
  
  Reply
Phil from South Carolina

April 14, 2018

Just got my chlorinator running again. Had to change out the flow switch. Pool was green. Pool company told me in the mean time, add a double dose of Bioguard banish and 2 more bags of burnout 73. Green is gone but cloudy enough to only see about 2 feet down. Just tested the water and chlorine is off the chart (above 5) and pH is likewise off the chart high ( greater than 8.2). How do I get this down? Bleed and feed?

Reply
1. Matthew Simmons
  
  April 16, 2018
  
  Use pH reducer or muriatic acid to lower the pH to the correct range. Then use a clarifier or flocculant to get rid of the cloudiness (the dead algae.)
  The chlorine will burn off, so that is not much of a concern.
  
  Reply
Eric from Jacksonville

May 1, 2018

Hey Matt, thanks for the guide, it is a good simple breakdown. I have a salt water pool in N. FL that gets full day sun. My FC is always maxed out on the local store test of 5ppm, could be higher. Due to this I turned my salt cell output from 70% to 50% and let my stablizer fall to 30-40ppm, hoping to reduce FC. Even at 50% output for week with my salt at 3200ppm my FC is above 5ppm, what can I do to get this in check, should I lower the output more espically going into summer? Also my PH is always testing at 8 so we add a quarter gallon muratic acid weekly. All the sudden my test shows a PH is at 7.6 and my Total Alkalanity is at 75ppm, every other test it was at 100ppm. Is my total alkalanity a diret product of my PH, meaning when we try to lower PH with muratic acid it is also lowering total alkalinity? If so why can’t I get my PH under 8 and my total Alkalnity withhin normal range at same time? Am I splitting hairs? How do I get this thing balanced.

Reply
1. Matthew Simmons
  
  May 4, 2018
  
  Lower the chlorine output to 30 or 40 until the FC gets back in check. The excess chlorine will eventually get used up and you’ll see the FC drop.When it gets back to a desirable level then you can go back up to 50 percent. I don’t know the size of your pool or the generator. But for an example, if you have a 40K salt generator and you only have a 15K gallon pool you are overdosing the pool. When the hotter days come you can up the dose as necessary.
  
  Muriatic acid will bring down both pH and alkalinity. Saltwater pools have a naturally higher pH, that is why you always have to keep an eye on it.
  
  Reply
2. Pool elf
  
  November 29, 2018
  
  The reason your PH is always going up is from the salt cell making bubbles as it turns salt into chlorine. This is also called aeration which will only effect the PH to go up but not your Total Alkalinity. So what you will find is that as you have to add Muriatic acid to lower your PH it will also lower your Total Alkalinity and you will have to add Bi Carb. which is baking soda to raise your Total Alkalinity back up to standard all the time. Get used to it as this is how salt water systems work when you want to make your own chlorine. A salt water pool makes a pool’s PH & TA a roller coaster going up & down compared to a normal chlorine pool which has liquid chlorine added as needed as they stay more stable as they don’t have aeration constantly going into them.
  Lowering & adjusting the run time along with the cell output to meet your pools chlorine needs is the best thing you can do as to many people turn their cells up to high & run them to long.
  
  Reply
  1. Tim DeWitt
    
    May 4, 2019
    
    I would challenge the assertion that you have to get used constantly adding chemicals to a salt water pool. After opening ours in the spring and spending a few days getting the chemistry adjusted (usually amounts to adding salt lost through pumping out water over the winter and a minor ph / alkalinity tweak) we rarely have to do anything to our pool to keep ph around 7.5 and TA around 100.
    
    Reply
Michael h.

May 16, 2018

I have a 20 x 45 pool. It is only 7 ft deep instead of 8, so I think about 37000 gallons. I take care of it myself. Salt generator, and de filter. We had electric heater but just added a propane unit. I am told the pipes will corrode easily if ph is low.
I don’t want to depend on the colored dipsticks. Can you recommend a step up for alkalinity, and ph testing. ( my generator shows chlorine levels)

Reply
1. Matthew Simmons
  
  May 17, 2018
  
  There are electronic testers, but they still use test strips – Aqua Chek Trutest Digital Reader – NP207
  
  Your generator model may have an add-on accessory like a Sense and Dispense system that can read pH and alkalinity snd then disperse the necessary amount of chemicals automatically. What model of salt system do you own?
  
  Reply
Marian M.

May 27, 2018

Hi Matthew, I’m replastering my pool. Do you have a start up for plaster or is it the same procedure as the pebble tel start up ?

Reply
1. Matthew Simmons
  
  May 28, 2018
  
  If you are replastering your pool, you need to hold off converting to saltwater for 60-90 days. Ask your plastering company for their recommendation to be sure though. Plaster needs time to cure. If you convert to salt too early after plastering, you are throwing a lot of money down the drain.
  
  Reply
Wayne E.

May 27, 2018

have a 27000 gallon salt pool. Salt generator registers 3200. Electronic Aqua check strips read:
cl-0.0
ph-7.3
akl-130
How can I raise my chlorine level?

Reply
1. Matthew Simmons
  
  May 28, 2018
  
  You’re missing a really important value, the stabilizer, CYA levels. Can you post that as well? That will help to figure out if your CYA levels are super high, which can harm the effectiveness of your chlorine?
  
  But if you want to raise your chlorine quick, use shock, liquid chlorine, or bleach.
  
  Reply
Tim

June 25, 2018

My pool is cloudy and am having a problem getting it to clear up. I had my water tested and here are the results. Help please!
PH 7.7
FC 1.7
TA 82
Total Hardness 70
Salt Level 26

Reply
1. Matthew Simmons
  
  June 26, 2018
  
  Your hardness reading is very low, it could be the cause of cloudiness. When your calcium hardness is that low, the water begins to leach from the pool surface. The calcium hardness should be around 200 – 400 ppm.
  
  Reply
Brad Heath

July 5, 2018

Hi, I am struggling with getting the pH down. These are my numbers:
Cl- 2
pH-8.5
TA-180
CY-30
Calcium-300
Salt-3130 Pentair chlorinator runs 12 hours at 60%

Any suggestions are appreciated!
Thank you,
Brad

Reply
1. Matthew Simmons
  
  July 6, 2018
  
  Salt pools run at a higher pH, so battling that is going to be a constant. There isn’t much of a tip for this, you would need to add enough pH Down or soda ash to bring it into check.
  
  A helpful tool in figuring out how much of each chemical or balancer needed for your pool is PoolMath Calculator.
  
  Reply
2. MynameisJEFFFFFF
  
  July 25, 2018
  
  Your alkalinity is too high. It will cause the PH to be constantly higher
  
  Reply
3. Jason
  
  July 26, 2019
  
  Purchase pentair intellichem it would monitor and add acid and keep your ph in check fantastic product
  
  Reply
Caroline wiltfang

July 7, 2018

We have a 12×24 oval above ground salt water pool. Salt level is 3300. Our ph is high. Alkalinity high and free chlorine is 0. Just cleaned out the salt cell as it was corroded with deposit after only 2 months. Cannot get the alkalinity or chlorine at the right levels. What are we doing wrong? How often should we need to shock a salt water pool?

Reply
1. Matthew Simmons
  
  July 8, 2018
  
  Salt pools, naturally run a high pH. But we will start with the chlorine issue first. Units like the Aquarite usually need a cleaning every 500 operational hours. So, if you have you chlorine set to run 50 percent of the time, and you run your pump 24 hours a day, then that is 12 operational hours per day put on the cell. hours can rack up quick, depending on how you run the cell. The cell was likely lagging because it was so dirty. To help figure out how much chemical you need to add for each category, try this Pool Math Calculator
  
  A salt shouldoft need to be shocked but maybe once or twice, outside od opening and closings. The chlorinator should be able to handle anything you throw at it. Shock should only be a tool to help give the chlorinator a boost if you need to add fresh water or after a large gathering of swimmers.
  
  Reply
Caroline wiltfang

July 7, 2018

Also our stabilizer levels are perfect

Reply
Kevin

July 21, 2018

I have a few month old pebble tech salt water pool. The test strips show Alkalinity low and CYA low.

A digital tester reveals the following:

FCL 2.14
TCL 2.14
PH 7.7
ALY 64
CH 235
CYA 38

What if anything do you suggest?

Thank you

Reply
1. Kevin
  
  July 21, 2018
  
  Salt is 3200
  
  Reply
2. Matthew Simmons
  
  August 3, 2018
  
  This digital tester, is it one you purchased or did you get it tested from a local pool store? I always lean towards pool store results being the most accurate. I especially trust the pool store tests more in the case of a conflict in results such as this. Test strips can be fouled, and digital home test kits can be a great tool but finicky. If you haven’t already gotten a pool store water test, that should be your next step.
  
  Reply
Melissa

July 29, 2018

How is everyone getting exact measurements? I have an 18′ x 52″ intex pool with a saltwater system. We have hard water in my area and I’ve added hardness reducers for that. We also always have high ph and alkalinity. I’ve added muriatic acid and now it’s too low. I had done an acid demand test and added the amount required. I’ve googled this so many times but I don’t get the answers that are working. Please help

Reply
Melissa

July 29, 2018

I also want to mention that the water is perfectly clear, always. I noticed that my niece’s hair was super tangled after swimming and that’s why I tested the water. I have a 5 way test kit that I use and the test strips. My chlorine and free chlorine are low and so was the stabilizer. I added stabilizer 2 days ago but I’m not sure what I should do next. Do I shock it or just let the salt cell do it’s job? I clean the cell every couple of weeks because of the calcium build-up.

Reply
Dane

August 1, 2018

We’ve had saltwater system for three months. Pool is clear, salt meter is at 28-29. We have a T-15 T cell and the light is blinking to indicate a need to clean it. I’ve cleaned it but not with muriatic acid (still blinking). Ph and alkalinity are at high end. All other readings are good. This is a Hayward system.

Reply
1. Matthew Simmons
  
  August 2, 2018
  
  Then I would let muriatic acid have a crack at it. I’m not sure what you are washing it with but there is a reason the standard method uses MA, it works.
  
  Reply
Tony

August 29, 2018

I have a salt water pool for two years and am having trouble balancing the Total Alkalinity, which is often low (40). I have the water tested at a pool store and I follow their recommendations to add Sodium Bicarbonate at the recommended dosage, turn off the acid bath for a few hours until the powder dissolves. Recheck the water and add more if needed to bring TA to ideal levels. It stays good for 7-10 days. Then goes off again. As a result my pool has become green three times this year! How do I maintain a perfect balance?
My pool is 8×4 meters wide, 1.6 m at the deep end (48 cubic meters, correct?). The latest pool water reading is pH 7.8, Free Chlorine +10, Total Alkalinity 40, TDS 5.54, and Cyanuric Acid 30. I have a Zodiac Tri Expert with pH and ACL auto adjustments. Six weeks ago I calibrated the pH and ACL electrodes, and have cleaned the salt cells, but there is again build-up in the cells so I need to again clean them.
Please advice.

Reply
SurajSharma

November 12, 2018

I have salt water pool. Chlorine level is perfect but ph is low. As you mentioned that salt water pools have high ph and you have to add acid then why my pool have low alkanity. There is enough salt in the water.

Reply
1. Matthew Simmons
  
  November 14, 2018
  
  Have you recently added acid to the pool? Or some other pH-reducing agent? That would explain it.
  
  Reply
Jill

February 14, 2019

I have a 345 gallon, salt water spa and am having problems balancing the ph and the alkalinity.
Alk is 180. Ph is 6.8 and sometimes lower. Salt is 1750. Hardness, Bromine and Chlorine are good.
I drained it and started over and it still creeps back to the same problem. It does not get direct sun and I live in Montana. Suggestions? Thank you!!!

Reply
Carol

April 24, 2019

I have a 4400 gallon salt water pool and I’m having problems with all of my levels. All are low but the free chlorine is very high. What do I do?

Reply
1. Matthew Simmons
  
  April 24, 2019
  
  Can you provide the results of your latest water test so I know what we are dealing with?
  
  Reply
Jon

April 30, 2019

I work on 106000 gal Pool salt levels are at 3600-3800 but chlorine levels are low all the time. I thought salt should turn into chlorine am I missing something?

Reply
1. Matthew Simmons
  
  April 30, 2019
  
  What model salt chlorine generator do you have installed on your pool?
  
  Reply
Maggie

June 8, 2019

I have a hayward saltwater cell, my salt is low, because I’ve been trying to raise my stabilizer levels and my TA. Well my stabilizer is in range (50) just today, and my TA is now 120. Now I want to raise my PH it is 6.8. How do I raise it without raising my TA? My FC and TC are both zero right at the momoment. I do have a waterfall. Do I just let aeration raise it?

Reply
Michael

July 9, 2019

Hello

I have a Intex sand filter and salt water system
Model EXO20110-1

6543 gal steel frame round vinyl

Free chlorine is ok

On test strip:

TA LOW
PH LOW
CALCIUM HARDNESS LOW

What chemicals and amounts do I need to get these in the ‘ok’ zone?

Reply
Beth

July 21, 2019

Calcium is too low and so is Ph in my saltwater pool. What should I do?

Reply
1. Matthew Simmons
  
  July 22, 2019
  
  You’ve basically answered the question already; your pH and Calcium are too low, so that means you will need pH and Calcium Hardness increaser. For all your other pool chemistry balancing needs, visit this page, Pool Balancers – INYO Pools.
  
  Reply
Frank in Minnesota

August 3, 2019

Hi,
Salt-water pool 20-30′ plastic liner
According to my home water test kit:
pH=72
Total Alkalinity = 220

How do I get my alkalinity in line with 60-80 ppm recommendations without affecting my pH?

Reply
1. Matthew Simmons
  
  August 5, 2019
  
  To lower your pH, add muriatic acid or pH decreaser.
  
  Reply
Norman

August 4, 2019

This is an interesting article. There is one point where there seems to be conflicting views in the industry and that is the relationship between FCL and CA. For salt water pools the consensus seems to be about keeping the CA between 60 – 80ppm ( let’s say 70). Now due to the higher CA levels there is a lot a indications that the FCL levels need to be higher – the proposed formula is to put the FCL = 7.5% x CA. Using the proposed CA target level of 75ppm, this puts the FCL target around 5-6ppm. In your article you indicate still keeping the FCL between 1-3ppm. Interested in your thoughts. Thanks.

Reply
Scott

January 25, 2020

I am having a problem of keeping my saltwater pool balanced. The pool has a waterfall from the spa. No matter what I do the pH goes up every three to four days. I then add muriatic acid to get the pH back down and before you know it my total alkalinity is down and I need to add baking soda. Them the Merry go round starts again. Chlorine is 2, pH is 7.6, total alkalinity is 80, hardness is 280, and my cyanuric level is 50. I have the saltwater chlorinator off as water temp is 46. I have a peeblesheen finish. What am I doing wrong, or is this something I need to live with.

Reply
1. Matthew Simmons
  
  February 17, 2020
  
  You’re not really doing anything wrong. But if you run your waterfall a significant amount of time then you are going to continue to have pH issues. I’d only run the waterfall when it was necessary (like parties) to prevent the spike in pH.
  
  Reply
Justine

January 31, 2020

Our pool builder continues to tell us that our Chlorine levels do not matter in our Salt water pool. We’ll take the water to get tested and they’ll say our chlorine is high, like 7. Salt level is ok. So the pool store says to turn our chlorine generator down to like 10-20%. Our pool builder came out for a service on our equipment and put it back up to 60%, saying that chlorine readings on a salt water pool don’t matter. Is this true? I am most concerned for our health and long term life of our equipment. Any insight is appreciated!!

Reply
1. Matthew Simmons
  
  February 17, 2020
  
  Tell your pool builder to stop touching the equipment, because he doesn’t know what he is talking about. Yes, the chlorine level matters in any pool that uses chlorine as its main sanitation chemical. Your Free Chlorine (FC) reading should be between 1 – 3 ppm.
  
  Reply
Charles

April 10, 2020

I have a salt water pool in an area of extremely high calcium. The chemical balance has been good with the exception of calcium – which is off the chart high. I added 2 liters of Zodiac Calcium Down to the 40000 liter pool and overnight the pool went from lovely and clear to VERY milky with LOTS of ‘white powder’ coating the pool steps and presumably the bottom.

I assume this is calcium particles no longer held in solution?

The instructions stated the water color would change and to run the filter for 72hrs. So far it’s been 48hrs. I’ve backwashed twice. The backwash looks like white paint.

Anything else I can do or is it just a matter of patience as the calcium is filtered out?

Reply
1. Charles
  
  April 10, 2020
  
  To add the calcium is so high that within 24-48hrs of cleaning the elements they are heavily coated with calcium and then it starts breaking off and depositing chips of calcium into the pool. A few hours before adding the calcium down I added 80kgs of pool salt as we had just come out of a 3 week period of persistent rain.
  
  Reply
  1. Matthew Simmons
    
    April 14, 2020
    
    I’d give it another 24 hours if I was in your situation; a lot can change in that time. Did you add pool shock and an algaecide at the same time? This common chemical mistake can also cause milky water.
    
    Also, I am very skeptical of “calcium down” chemical additives. The most reliable way of getting your calcium down is draining a portion of your pool and then refilling with fresh water. But if your local water has a high calcium content, it likely is your only option.
    
    Reply
    1. Charles
      
      April 15, 2020
      
      Thanks.
      
      I’d a.ready given it another 24hrs – then drained the pool. There really was no change in milkyness and the bottom of the pool was covered in white slime – I still think it was calcium.
      
      Gave the pool and good cleaning with our water blaster and it’s currently refilling.
      
      Won’t make that mistake again.
      
      Reply
Mandy

April 13, 2020

Hi! We have newly built salt pool..7000 gallons.
I went to the pool store to have the water tested today and our chlorine is at 0!! PH was 8, alkalinity was 120, stabilizer was 60. I don’t really want to shock the pool with liquid chlorine so how do I slowly bring it back? I added the muratic acid already and will test again tomorrow. Am I on the right track to bring up the chlorine levels? Water is clear. Trying to figure out how these chemicals work together???

Reply
Stefanie

June 4, 2020

We are new salt water pool owners and we recently opened up our pool. We can’t seem to get our pool balanced. When trying to balance a pool, is there a preferred order when trying to correct? Our pH is low (7.0) , Alkalinity High (175), Total Chlorine Low (0.71), Cyanuric Acid Low (18), Salt 3816, Total Hardness (195), Copper (0.3).

Also, Total dissolved Solids, I have read can be higher in salt water pools. Do you know what the recommended range is for the salt water pool?

Reply
1. Stefanie
  
  June 5, 2020
  
  I almost forgot to mention, we live in rural Illinois, so our Phosphate Levels are also really high (~4500).
  
  Reply
Shane

June 5, 2020

Hey Matt. Just bought a house with pool and the company that opened the pool didn’t do a great job adjusting the chemicals as there is algae growing as easily as overnight. I just tested the water and got readings as follows but not sure what chemicals I should be using for each and in what order, would you be able to help?

PH – 6.8
Free chlorine – 0
Total Alkalynity – 0
Stabilizer – 0
Salt – 3.8 or 1040ppm

Reply
1. Matthew Simmons
  
  September 22, 2020
  
  It looks like you need to increase everything; your pH, alkalinity, chlorine, stabilizer, and salt are all low. In the article under each heading, we provide the correct ranges for the various chemicals.
  
  First, you need to calculate the number of gallons in your pool, then you can use a pool math calculator to judge how much of each water balancer you need to add.
  
  Reply
John Nicely

October 1, 2020

Trying to balance pool pH above 8.2 purple,CL above 3.0 dark orange.Salt water pool,fiberglass, inground, with auto safety cover closed all the time,now. Chlorine generator down to 10%. pool size is 4′.4″deep in shallow,6’6″deep in deep end.14.5 wide x 35′ long.

Reply
1. John Nicely
  
  October 1, 2020
  
  When calculating gallons do I need to divide the differance between the shallow and the deep.
  
  Reply
2. Matthew Simmons
  
  October 5, 2020
  
  I would use a regular old pool volume calculator top get a general idea.
  
  Reply
Lori

June 1, 2021

I have a 30,000 gallon 20×44 salt water pool. Chlorine is good 1.5ish, ph is usually in good range 7.2 ish. The salt level is good. The biggest problem is alkalinity at around 250-260ppm. We have added many gallons of MA over several weeks and the numbers have come down from 320 but should we keep adding MA? Or just work with PH up or PH down products?

Reply
Bill Thompson

June 17, 2021

Hi
Thanks an interesting article
Do you have any recommendations for test equipment- – wo have a small above ground saltwater pool with a intex chlorine generator. We struggle with test strips /ph meters to get any two methods/strips to give a similar result.

Reply
1. Nik
  
  June 26, 2021
  
  I have same problem with an in ground saltwater pool. I use two different methods to test and get two different results.
  
  Reply
  1. Matthew Simmons
    
    August 4, 2021
    
    The best thing to do when dealing with conflicting home test results is to get a sample tested at a local pool store. These tests are usually free and should be more accurate than most home kits you can buy.
    
    Reply
2. Geek
  
  September 3, 2022
  
  Taylor drops are much better than strips
  
  Reply
Robert Price

December 21, 2022

Do you offer a pH tester that shows a higher range for use with salt water pools? With minimal acid my test kit maxes out at 8.2 pH.

Reply
1. Matthew Simmons
  
  January 3, 2023
  
  The pH range for a test kit I found was 8.4. If you search for the “High Range pH Test Kit” through google or bing, there are specialty options that go as high as 8.8. I presume pool test kits top out at 8.2 because it is rare a pool would be out of balance that badly, and if a pool did reach those levels, it is likely a dump-and-fill reclamation project.
  
  Reply
2. Robert Price
  
  February 10, 2023
  
  Thanks for your answer. I am finding that my salt water pool needs more acid than I am comfortable putting in. I have learned from previous spa ownership that it is not good to add too many chemicals. Helps to promote drain and fill.
  
  Reply