How To Test And Fix Pool Water

Prep your pool water for this holiday season! Be your own pool guy with our super simple DIY pool water test guide. First things first. To test your pool water use the Aquachek 7 in 1 test strips to see if your water chemical balance is too low, too high, or just right. At $49.99 it contains 100 strips which will keep you going for 2-3 years: 

 

Aquachek
7 in 1 Test Strips

 

For home testing, test strips is our personal favourite. It’s easy to do and very accurate – much more accurate than using a liquid test kit because of human error when it comes to matching up the colours and using chemical droplets.

Take your water sample and quickly dip one, dry strip into the water. Hold it still in the air for about 10 seconds (do not shake off the excess water). Then match up the colours of the strip to the back of the bottle to get your readings.

Use your Aquachek 7 in 1 Test Strips to run through the below results from top to bottom of the test results strip:

 

Calcium HARDNESS:

Too low

What does it mean?
Having low calcium hardness levels means the water is very aggressive and is extracting the calcium out of the pool walls (concrete pools only) which appears to be a crystallisation of calcium build up. The common mistake is that people assume this is due from TOO MUCH calcium, which is not the case. Aggressive water can also damage metal equipment (salt cells, heating elements etc) prematurely due to corrosion.

 

How to fix it?
Dose your pool with Calcium Up. You can follow the dosing instructions on the back of the packet, though we recommend adding the whole 4kg bag to your pool for optimum results.

 

Zodiac
Calcium Up 4kg

Too high

What does it mean?
If the water is saturated with calcium, you will see scaling on pool equipment (salt cells, heating elements) causing reduced efficiency in these products. Pool water can also become cloudy.

How to fix it?
By adding Calcium Down to reduce the levels, along with testing and balancing the pH to ensure correct levels are maintained.

 

 

Zodiac
Calcium Down 1L

 

FREE CHLORINE:

Too low

What does it mean?
Your pool isn’t sanitised. Middle ear infections and a green or cloudy pool is on the horizon!

Reasons it could be low:

  • Not enough salt in the water for your Chlorinator to produce chlorine (salt should sit around 5000ppm (parts per million)).
  • Salt cell needs cleaning.
  • Salt cell needs replacing. Salt cells have an average life span of 4-6 years.
  • Chlorinator needs replacing. Chlorinators can die for a number of reasons:
    - 8 to 12 years old is the average Chlorinator life span
    - The Power Board or PCB Board (the brains of the Chlorinator) has seized.
    Sometimes it's better and easier on your back pocket in the long run to replace than fix.
  • If you're not sporting a Chlorinator (shame on you), you’re not manually dosing it with enough liquid or granulated chlorine.
  • Your Cyanuric Acid (UV Blockout) level is low, therefore majority of the chlorine in the water is getting evaporated by the sun.

How to fix it

  • If you're sporting a Chlorinator, add salt. Salt should sit around 5000ppm (parts per million). Each 20kg bag of salt equals roughly 500ppm for 60,000L pools.
  • Clean your salt cell (give it an hydrochloric acid bath in 10% acid 90% water for 3-5 minutes until majority of the calcium bubbles up and dissolves).
  • Replace your Chlorinator Salt Cell.
  • Replace your Chlorinator.
  • Use granulated chlorine instead of liquid chlorine and add 1-2 cups - it's much stronger. Always choose NON-stabilised granulated chlorine.
  • Dose your pool with Cyanuric Acid (UV blockout/stabiliser). Always follow dosing instructions on the back of package and never add more than 500g-1kg of Cyanuric Acid at a time.

We're not able to ship Chlorine as it is a dangerous good, though we charge $12 for 25L Liquid Chlorine and $80 for 10kg Non-Stabilised Granulated Chlorine at our shop front in Gosford, NSW.

 



Salt Cells
FROM
$145


 

 

Chlorinators
FROM
$890




Zodiac
Cyanuric Acid
(UV Blockout, Stabilizer)


 


Too high

 

What does it mean?

Too much chlorine in the water can be harmful to swimmers and cause skin and eye irritations. Green hair incoming!

Reasons it could be high:

  • Your pool has been over dosed with too much liquid or powder chlorine.
  • Your Chlorinator is turned up too high.
  • Your TOTAL chlorine level is high (and your FREE chlorine is low) but ineffective due to a “chlorine lock”, which happens when too much Cyanuric Acid is added to the pool.

How to fix it?

  • You can get “chlorine remover” chemical if it is urgent. Though, this is expensive and may end up costing you an arm, leg and your first-born. If it's not urgent, the sun will naturally dissolve excess chlorine within 3-5 days in exposed sunlight.
  • Turn your Chlorinator down to its lowest setting (10-20%)
  • If you're manually dosing your pool Liquid Chlorine or Granulated Chlorine, stop adding Chlorine until it is back down to normal range on your test strip. Avoid swimming, or wear goggles if you do.
  • Check Stabiliser (UV Blockout) levels and ensure that levels are a max 30 - 50ppm on your test strip. If higher, caution will need to be taken to remove water from the pool and refill with fresh water.

     

    pH


    Too low

    What does it mean?
    High pH water corrodes metal surfaces and pool components such as ladders, railings, screws, pool light fixtures, as well as metal surfaces in your pump, filter system, and heater.

    Reasons it could be low:

    • You have added too much hydrochloric acid.
    • You are currently adding excess acid to lower your pH to fix an algae problem in your pool.

    How to fix it:
    Add Alkalinity Up (sodium bicarbonate/buffer) to the pool with applicable dosage rates to your pool volume. As a general rule 1.75kilos of Alkalinity Up will raise the pH of an average backyard pool of 32 m2, or approximately 42,000 litres of water, by 1.1.

     

    Zodiac
    Alkalinity Up

     

     

    Too high

     

    What does it mean?
    If it isn’t already, your pool will start to turn green soon. Or, you may be having blackspot algae issues. Algae loves high pH. Also, chlorine isn’t as effective when pH is high.

    Reason’s it could be high:

    • Your phosphates are high. Phosphates are caused by debris sitting in the bottom of your pool, such as leaves and run-off after a storm. 
    • You haven’t dosed your pool with hydrochloric acid for a few months.

    How to fix it:
    Dose your pool with Hydrochloric Acid. 1-2L of it to start with. Be careful when adding it to make sure it doesn't splash up on you as it is highly toxic and dangerous, and only add 1L every 24 hours if your pool is Vinyl lined as it's more sensitive to harsh chemicals. pH should sit around 7.5, if you're having a blackspot algae problem, keep our pH at around 7 for 2-3 months and watch that slowly dissipate.

    We're not able to ship Hydrochloric acid as it is a dangerous good, though we charge $15 for 5L at our shop front in Gosford, NSW.

     

    ALKALINITY

    Too low


    What does it mean?
    Water could be quite acidic and causing damage to equipment or etching on pool surface.


    Reasons it could be low:
    Incorrect pH balance or frequently back washing.

    How to fix it:
    Add Alkalinity Up to the pool with applicable dosage rates to your pool volume. As a general rule 1.75kilos of Alkalinity Up will raise the pH of an average backyard pool of 32 m2, or approximately 42,000 litres of water, by 1.1.

    Zodiac
    Alkalinity Up

     

     

    Too high

     

    What does it mean?
    The problem with unbalanced alkalinity levels is mainly how it affects the pH levels, which can result in them being too high.

    Reasons it could be too high:
    One of the main reasons pool alkalinity can get too high is when you have added too much Alkalinity Up when you were trying to raise it.

    How to fix it:
    In very rare cases, your total alkalinity may be high but with a low pH in the same pool. If so, using muriatic acid directly to lower Total Alkalinity is not a good idea since this will further lower pH down to very dangerous levels for a swimming pool.

     

    CYANURIC ACID

    Too low


    What does this mean?
    The sun will be dissolving any chlorine added to your water quicker than usual.


    Reasons it could be low:

    You haven’t dosed your pool with Cyanuric Acid (UV Blockout) for a few months.

    How to fix it:
    Dose your pool with Cyanuric Acid. Always follow dosing instructions on the back of package. We recommend adding it in lots of 500g. You can always add more, but can’t take it out if you add too much.

     

    Zodiac
    Cyanuric Acid

     

     

    Too high


    What does this mean?
    Your water could be in a chlorine lock, meaning that the chlorine level is high but has no effect on the water. 

    Reasons it could be high:

    • You have dosed your pool with too much Cyanuric Acid.
    • You are frequently using Stabilised granulated chlorine (big no, no).


    How to fix it:

    The only way to fix this is by emptying the pool. Always talk to a pool expert for advice before emptying a pool.

     

    SALT


    Salt testers are expensive, so we recommend taking a sample of water down to your local pool shop to get this test. You only need to test for salt 2-3 times a year.


    Too low


    What does this mean?
    Your chlorinator will not have enough salt to produce chlorine to its full capacity.

    Reasons it could be low:
    You haven't dosed your water with salt in 6 months or over.

    How to fix it:
    Add bags of salt to your pool. Your salt level should be sitting at 5000ppm (parts per million). Each 20kg bag of salt equates to 500ppm for an average 60,000L pool.

    We're not able to ship Salt, though we charge $12 for 20kg at our shop front in Gosford, NSW.

     

    Too high


    What does this mean?
    It’s not the end of the world, as it will dissipate over time, but could affect your pool equipment in the form of rust.

    Reasons it could be high:

    Too much salt has been added

    How to fix it:

    You can empty 20% of your pool and re-fill it, or simply let the salt in your water dissipate over time and don’t add more salt until it’s back down to 4000ppm-5000ppm level.

     

    Other blog posts which may help you are:

    How to test and fix pool equipment

    How to get rid of pool algae (green pool water)

    How to get rid of black spot algae

    How to fix cloudy pool water

    How to backwash a sand filter

    Post author:

    Natalie Hintze

    Head of eCommerce & Marketing at Mr Pool Man,
    Co-Founder at Water TechniX

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