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Water Chemistry For Saltwater Pools

– 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

pool-maintenance-checksBefore 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.

cyanuricAcidSTEP 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

P37025DESTEP 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

P31002DESTEP 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.

author avatar
Charlie Ramirez
Writer at InyoPools.com, brings a wealth of knowledge and expertise in pool care and equipment, helping pool owners make informed decisions for over a decade.

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89 responses to “Water Chemistry For Saltwater Pools”

  1. Jon Avatar

    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?

    1. Matthew Simmons Avatar

      What model salt chlorine generator do you have installed on your pool?

  2. Carol Avatar

    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?

    1. Matthew Simmons Avatar

      Can you provide the results of your latest water test so I know what we are dealing with?

  3. Jill Avatar

    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!!!

  4. SurajSharma Avatar

    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.

    1. Matthew Simmons Avatar

      Have you recently added acid to the pool? Or some other pH-reducing agent? That would explain it.

  5. Tony Avatar

    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.

  6. Dane Avatar

    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.

    1. Matthew Simmons Avatar

      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.

  7. Melissa Avatar

    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.

  8. Melissa Avatar

    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

  9. Kevin Avatar

    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

    1. Kevin Avatar

      Salt is 3200

    2. Matthew Simmons Avatar

      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.

  10. Caroline wiltfang Avatar

    Also our stabilizer levels are perfect

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