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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. Robert Price Avatar

    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.

    1. Matthew Simmons Avatar

      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.

    2. Robert Price Avatar

      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.

  2. Bill Thompson Avatar

    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.

    1. Nik Avatar

      I have same problem with an in ground saltwater pool. I use two different methods to test and get two different results.

      1. Matthew Simmons Avatar

        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.

    2. Geek Avatar

      Taylor drops are much better than strips

  3. Lori Avatar

    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?

  4. John Nicely Avatar

    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.

    1. John Nicely Avatar

      When calculating gallons do I need to divide the differance between the shallow and the deep.

    2. Matthew Simmons Avatar

      I would use a regular old pool volume calculator top get a general idea.

  5. Shane Avatar

    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

    1. Matthew Simmons Avatar

      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.

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