How To Maintain Pool Water Chemistry
Poolmaster 22270 5-Way Test Kit with Case on Amazon
Pool Water Chemistry is used to keep your swimming pool’s water balanced. It’s something as a pool owner I had to learn. Water that is balanced makes it easier to keep the pool clear and clean. This is a hard fact. Keeping water within a range is something that is not hard to do if you pay attention to the amount of time since the last time you added chemicals. A mixture of pool chemicals prevents algae from growing and keeps your water ready for swimming.
At this point, you may be thinking you will need a bunch of different chemicals to keep your water balanced. This couldn’t be farther from the truth. The truth is that with one chemical for PH control and a sanitizer you can keep that water crystal clear and sparkling.
So what do you need to control?
Here’s the list
- PH
- Free Available Chlorine (FAC)
- Total Available Chlorine (TAC)
- Calcium Hardness
- Total Dissolved Solids(TDS)
- Total Alkalinity
- Cyanuric Acid (Water Stabilizer)
Other Factors that impact Pool Water Chemistry
Before we get into pool water chemistry, you need to know that there are other things that will impact your hardest efforts at maintaining your water clarity. If the water is not being effectively filtered and circulated you will fail. If the pump is undersized, or not run long enough every day or the filter is broken, too small, or not functioning correctly your water quality will suffer.
Filtration removes suspended matter such as dirt, leaves, dead algae, organic matter and other debris from the water. Circulation brings the water to the filter and it assures that the chemicals that have been added are being spread throughout the pool. So what this all means is that a clean filter in good condition along with a good pump running long enough every day will go a long way to making your efforts at pool water chemistry successful.
Pool water chemistry ranges
For a long time, I accepted the test numbers as being good if they were in the desired range. Boy, was I wrong. I had a series of ups and downs trying to control my pools water quality. What I mean by this is that if for instance, say the pH is at the high end of the range say 7.8 yes it’s in the range but one number and it’s no longer in range.
In my area, we live about 50 miles from the California Delta’s peat bogs. That material is great for Asparagus growers but it is always in the air and it is continually pushing my pool’s pH up. So for me, I start my pH at the lower end of the range. It takes time to climb to the high end of the range and makes my pool water chemistry so much easier to maintain.
Shock and pH control
A example of Pool Water Chemistry test results
This is one of the latest bits of information I have picked up. Shock will impact pH levels. A sanitizer impacting pH levels. Whenever I am going to shock the pool I make sure that the pH level is at the lower end of the range. This way the shock will continue to work at peak effectiveness when it is added to the pool water. An instance of one chemical tipping the scale causing another to fall out of balance, which can lead to poor water quality.
pH
Ideal Level: 7.2-7.8
The pH of your pool water indicates how acidic the water is. The pH should lie between 7.2 and 7.8. When trying to balance pool water, use a pH increaser (sodium carbonate) when the pH is low, or acidic. Use a pH reducer, muriatic acid when the pH is high, or basic/alkaline.
The most common liquid acid used to lower the pH is muriatic acid, also known as hydrochloric acid. To raise the pH, soda ash(sodium carbonate) is normally used. Sodium bicarbonate(baking soda) should be used to raise alkalinity; it can be used to raise pH only if the alkalinity is low.Aug 16, 2017
How Much Muriatic Acid to Add to Adjust Swimming Pool pH …https://dengarden.com/…/How-Much-Muriatic-Acid-Should-I-Add-to-a-Swimming-Pool…
This is not an add acid situation and immediately add the other chemicals and call it good. When you add acid you need time for it to spread thru out the pool water. At least 4 hours of time for it to spread with the pool pump working the entire time to help spread it thru out the pool.
How I add Acid
I add a small amount of the total acid needed to a five-gallon bucket of pool water, mix it then spread it in the deep end of the pool. Then I repeat the process again with another small amount of acid until the required amount of acid is in the pool.
I choose to use this method over pouring it directly from the bottle into the deep end of the pool. There is less chance of the acid etching the plaster if it is diluted before being poured into the deep end of the pool.
Safely working with acid
- Remember to add acid to water. Do not add water to acid.
- Wear appropriate clothing(no shorts, flip flops, etc.) in case of a splash.
- Wear eye protection.
- Make sure there is adequate ventilation. Do not breathe the acid fumes
- Wet down the area before you start working with the acid to prevent accidental bleaching of the deck or concrete.
Free Available Chlorine (FAC)
Ideal Level: 2.0-4.0 ppm
Free Available Chlorine(FAC) is the amount of chlorine in the water that is available to sanitize and disinfect. The ideal range for Free Available Chlorine (FAC) is 2.0-4.0 ppm. Any FAC reading below 2.0 ppm or above 4.0 ppm needs to be addressed. A pool without enough FAC may not be able to overcome bacteria and algae that grow. A pool with too much FAC may be unpleasant to swim in, and cause bleaching or irritate eyes.
Leslie’s 9-point test http://www.lesliespool.com/9p/l.htm
Total Available Chlorine (TAC)
Total Available Chlorine(TAC) is the total of all the chlorine compounds in the water. When you subtract the (FAC) from the (TAC) that gives you the amount of Combined Available Chlorine(CAC). A(CAC) is a type of chlorine molecule that is contaminated and is no longer effective. Any level of(CAC) should be treated by oxidizing the pool.
Leslie’s 9-point test http://www.lesliespool.com/9p/l.htm
The tortoise and the hare
I’ll combine these two because both are dealing with chlorine but one is about chlorine that can work fast(FAC) and help in the fight against algae. The other is about chlorine(CAC) that can no longer work as fast, think of it as a turtle speed type of chlorine. The reality is that this type of chlorine(chloramine) is not a very good chlorine for disinfecting. It’s not very active at controlling algae and needs to be shocked out of existence.
How using shock destroys chloramine
Superchlorination
Chloramine can be removed from tap water by treatment with superchlorination(10 ppm or more of free chlorine, such as from a dose of sodium hypochlorite bleach or pool sanitizer) while maintaining a pH of about 7(such as from a dose of hydrochloric acid). Hypochlorous acid from the free chlorine strips the ammonia from the chloramine, and the ammonia outgasses from the surface of the bulk water. This process takes about 24 hours for normal tap water concentrations of a few ppm of chloramine. Residual free chlorine can then be removed by exposure to bright sunlight for about 4 hours.
From Wikipedia, the free encyclopedia https://en.wikipedia.org/wiki/Chloramine
Sanitizer
Sanitizer(Chlorine, Bromine or Biguanide)
Ideal Level: 1-4 ppm(Chlorine & Bromine), 30-50 ppm(Biguanide)
Your pool sanitizer is the bacteria killer for your pool water. Common sanitizers on the market are chlorine, bromine, and biguanides, with chlorine being the most common. Keeping sanitizer in your pool water prevents the growth of microscopic organisms which can lead to algae. Sanitizer must be added on a regular basis. Chlorine comes in many different varieties such tablets, sticks, liquid or granular form. It is important to never mix different types together as this can lead to bad chemical reactions.
Once you get a feel of how much sanitizer you need to keep the levels within range you will not need to check it so often. But be aware that a hot day or rain can use up your free chlorine quickly and trigger an algae bloom. I like my automatic offline chlorinator I add tablets to it and it dispenses sanitizer continuously for the entire week. I add one 8oz chlorine tablet for every 5,000 gallons of pool water.
Total Alkalinity
Ideal Level: 80-120 ppm
Testing for Total Alkalinity measures the amount of alkaline material in your pool water, which affects how resistant your pool water’s pH is to change. Keeping your Total Alkalinity in balance helps keep your pH in balance.
Total Alkalinity measures the water’s ability to protect and buffer the pH against rapid changes. The ideal range for Total Alkalinity is based on the type of sanitizer used but range between 80-120ppm.
Leslie’s 9-point test http://www.lesliespool.com/9p/l.htm
The range for Total Alkalinity when balancing pool chemicals is 80-120 ppm. Muriatic acid can also reduce high Total Alkalinity, special handling of the acid is needed, and extreme caution used if you chose to handle it.
I like that muriatic acid will help keep this within the range. It means that I don’t need to stock another chemical for the pool water. I always have to use acid for pH control so one action takes care of two parts(pH and Total Alkalinity) of the pool water chemistry.
Calcium Hardness
Ideal Level: 200-400 ppm
This test measures the calcium levels in the water. If there is not enough calcium, the water will become corrosive and damage the surface or equipment. Low calcium can be especially destructive to pools with tiles or plaster, as your water will leech the necessary calcium from your surfaces. If there is too much calcium, scale and stains can form on the surface. The ideal range for Calcium Hardness is 200-400 ppm.
Leslie’s 9-point test http://www.lesliespool.com/9p/l.htm
Total Dissolved Solids(TDS)
Maximum level: 3000 ppm
This test measures the amount of Total Dissolved Solids in the water. Total Dissolved Solids (TDS) are the mineral content in the water. When the TDS is too high, it becomes harder to keep the water in balance. You can also experience itchy skin, eye irritation, and cloudy water. The maximum range for TDS in most pools is 3000 ppm.
Leslie’s 9-point test http://www.lesliespool.com/9p/l.htm
Cyanuric Acid (Water Stabilizer)
Levels: 30-99 ppm
What is Cyanuric Acid: by definition as it relates to the pool and spa industry: Cyanuric Acid(CyA), also
known as stabilizer or conditioner, is a chemical compound that when introduced into a chlorinated
body of water will chemically bond to the HOCL. The CyA, when bonded, will protect the HOCL from the
sun’s ultra violet rays, in some cases allowing for chlorine residuals to last 3 to 10 times longer in
outdoor bodies of water. As stated by the NSPF, the ideal range for CyA in an outdoor body of water is
between 30 and 50ppm. Most state health departments permit a maximum of 100ppm of CyA to be
present in outdoor bodies of water and restrict the use of CyA, completely, from indoor bodies of water.https://www.haywardflowcontrol.com/pdf/literature/CAT_Controllers_Courier-30.pdf
The Bad Boys
These three, Calcium Hardness, Total Dissolved Solids(TDS), and Cyanuric Acid(Cya, water stabilizer, conditioner) are the bad boys of the group. Everything else in pool water chemistry is adjustable up or down. These three are not downward adjustable if you have too much of any one. The only way to drive the numbers down is to replace the pool water with fresh water. Adding water will not help it must be replaced. Or if you live in an area where there are pool water recyclers you can have your pool water drained and replaced by water that has passed thru a reverse osmosis system and had almost all the chemicals, minerals and organics stripped away.
Calcium
Calcium levels being too low will try and find a way to increase. If the water can get the additional calcium from the pool’s plaster it will. So for me keeping calcium in a safe range prevents the water from leaching calcium out of the plaster in my pool. This is pretty easy to do as I switch to Calcium Hypochlorite Pool Chlorine for the fall, winter and early spring months.
TDS
TDS is the sum of all the substances dissolved in your pool water. Everything you add to the water increases its TDS. Swimmers add to TDS thru any products on their persons. The air carries material that will also add to TDS. Periodically adding replacement fresh water to your pool will help keep your TDS level in check. The easiest way to lower your pool’s TDS level is to drain and refill it with freshwater, either partially or completely, depending on how high the level has become.
Cyanuric acid
Cyanuric acid or Cya is something that is added to chlorine sticks, tablets, small and large. Granular chlorine(Calcium Hypochlorite) typically does not have a stabilizer added. I use granular chlorine for the fall/winter/early spring seasons to reduce adding Cya to the pool water. I maintain that if you use the fall/winter rains you can easily control these three bad boys. Let the rain fill the pool. After one day of normally running the filter drain off the excess water back to normal water level. Do this for each rainfall and at the start of the pool season, your three bad boys will be in control.
Related Article: Winter Months and CYA Levels
How to Test for Pool Chemical Levels
Now that you know what you’re looking for, we can go through the methods of how to test the pool water chemistry. Pool test kits, test strips, pool stores these are the options for testing your pool water chemistry. You have different levels of test kits that will test all aspects of the pool water chemistry. Some, the basic test kits will only check a few items. You can also go to test strips which will test anything that you have the special strips for.
Or you can go to a local pool store and have them test a sample of your pool water. Just make sure that you place it in a clean container. Many of the pool stores will provide you with a container for your water sample. After the test they will advise you on what chemicals are needed and if you know how many gallons your pool contains they can tell you the exact quantities of each chemical you will need.
One thing you will need to know is that the test kit chemicals or reagents can get old and give you bad readings.
One common rule of thumb is to replace reagents at the beginning of each swim season. However, given proper care, many reagents can provide accurate and reliable results for longer than one season.
Date of manufacture is not the controlling factor when it comes to shelf life. Storage conditions are more important. Reagents are sensitive to environmental influences and will last longer under controlled conditions.
SWIMMING POOL TEST KIT REAGENT SHELF LIFE http://www.recsupply.com/reagent-shelf-life
To test or not to test that is the question
I have gotten comfortable with the pool water chemistry. I used to have a test kit that I would use but I no longer keep a test kit. My local pool store is my pool water tester. I can rely on them to have a fresh test kit to use on my water sample. There is no worry about reagent shelf life. They test my water and tell me what I need. I have my water tested once a month for normal conditions.
What chemicals do I have on hand for my pool water chemistry?
That’s it, basically it’s, two chemicals, chlorine, and acid.
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