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Easy Guide to Testing and Balancing Your Swimming Pool Water


Getting Started:

Testing and balancing swimming pool water can be a daunting task for a new owner, so today we’re going to guide you through the process. We’ll show you that with a couple of tools, knowledge and patience, anyone can do it.
What you’ll need
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Now we’re almost ready to start testing, but first we’ll have to get an approximate volume of our pool. To do this we use a simple formula: Length x Width x Average Depth x Multiplier = Volume in Gallons. The “multiplier” differs from pool to pool. For a rectangle, square or free-form pool, the multiplier is 7.5, while in a round or oval pool the multiplier is 5.9.
Once you have everything set up, it’s time to start testing. At minimum you should get a test kit that can test for Free Available Chlorine, Cyanuric Acid, pH, Total Alkalinity, and Calcium Hardness. These are the main items we’ll be balancing.
Before adding chemicals, it’s important to turn your pump on so that the chemicals will be circulated through the pool. Also, when working with chemicals, you can only add a certain amount of chemicals per 10,000 gallons of water at one time. If you need to add more than the maximum amount (per 10,000 gallons) then you will have to add it in increments. You should allow at least 6 hours between additions. Shocking a swimming pool is a device used to introduce large quantities of chlorine to the water at one time, maintaining or restoring chlorine balance.
Alkalinity: The first factor we want to address is the Total Alkalinity, or TA. Total Alkalinity refers to the quantity of alkaline material in the water. We do this first because alkalinity acts as a buffer for the pH. The ideal range for total alkalinity is 80-120 ppm. Depending on your readings you will want to add either a Alkalinity Increaser to increase the Alkalinity or a Sodium Bisulfate to decrease Alkalinity.
pH: The pH refers to the relative acidity of the water. Using the pH scale, which ranges from 1.0 – 14.0, we will want to get our water in the ideal range of 7.4 – 7.6. Anything with a pH level below 7.0 represents an acidic condition (low pH), while a pH level above 7.0 represents an alkaline condition (high pH). Depending on your readings you will want to add either a pH increaser (Sodium Carbonate) or a pH decreaser (Sodium Bisulfate). Keeping your pH properly balanced is important because an imbalance can cause structural and equipment damage.
Water Hardness: The next step in balancing our water deals with the water hardness. Calcium hardness refers to the amount of minerals, in this case calcium, which is present in the water. The ideal range for Calcium hardness is 200 – 400 ppm. To raise the Calcium hardness you will want to use Calcium Chloride. If you are experiencing high Calcium Hardness levels you will have to either drain the pool completely or partially.
Cyanuric Acid: Another factor we want to balance is Cyanuric acid. Cyanuric acid is sold as either a pool stabilizer or pool conditioner. Cyanuric Acid helps protect chlorine from being destroyed by the sun’s ultra violet rays, so it’s an essential ingredient. To achieve an ideal amount of Cyanuric acid in your pool you will need to be within the 30 – 50 ppm range.
Chlorine: Finally the last factor that we need to balance is our Chlorine. Chlorine is used as a sanitizer or disinfectant to kill any bacteria, living organisms, ammonia, or other contaminates in the pool. There are a couple of different options when it comes to Chlorine. It can come in a gas, liquid, granular, or tablet form. To have a balanced pool the Free Available Chlorine must be within the 2.0 – 4.0 range.You’ll be in the pool in no time.
Now that all the chemicals have been added it is ideal to let your pump run to circulate the chemicals in your pool. The whole process of balancing your pool water can be done on your own. So go ahead and give it a try. You’ll be achieving perfect water quality in no time.
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  • John Carbonara

    Do any of these steps differ if you have a salt generator system?

    • PoolSupplyWorld

      Hi John, the testing and balancing steps for a pool that utilizes a salt chlorine generator do not differ to that of a traditionally operating pool, aside from also testing the salt levels using a product such as AquaChek Salt Test Strips. If necessary in balancing your pool’s chemistry, you can even use chlorine tablets to supplement the chlorine produced by your salt chlorinator. However, you should be careful not to overload the system with chlorine as it could then give you false readings. Please let us know if we can be of any further assistance.

  • Rheta Record

    Does the hardness level (calcium chloride) matter in a vinyl liner pool?

    • PoolSupplyWorld

      Hi Rheta, while calcium hardness is not necessarily a major concern for vinyl liner pools, it is part of keeping pool water balanced, and discoloration of a vinyl liner may occur if your water chemistry is showing signs of high or low pH levels. Calcium hardness levels of vinyl liner pools should be around 80 PPM. You can test your pool’s water chemistry with AquaChek Select Test Strips. Please let us know if we can be of any further assistance.