Water Chemsitry Basics

Having a balanced water chemistry in your swimming pool means that all parameters of the water testing are within the ideal range to protect the water quality, equipment, and swimmers. Keep in mind that chemicals alone will not create clear water in the pool; circulation and filtration are important aspects as well.

All this information can be a little overwhelming, so let's start with the basics!

Filtration is to physically remove particles and debris from the water. While circulation moves the water to the filter and disperses the chemicals that get added.

Assuming your filtration and circulation are effective, take a look at the chart below to see the ideal levels when testing the chemistry.







7.4 - 7.6




80 - 120ppm



1.0 ppm

3.0 - 5.0 ppm

5.0 ppm


150 ppm

200 - 400 ppm

500 - 1000 ppm


pH: The measurement of how acidic or alkaline the water is. For the pH scale, a value of 1 is extremely acidic, while a value of 14 is extremely alkaline. Pure water is a value of 7, which is neutral. To lower the pH value, add a form of acid to make the alkaline value become more acidic. Our go to chemical for water balancing is Muriatic Acid. To raise the pH value, add an alkaline substance, such as Soda Ash to make the acidic value become more alkaline.

The pH is an important value for water chemistry testing. If the water is too acidic, it can dissolve metal it comes in contact with over time, potentially wreaking havoc on your pool equipment. Same goes for the opposite end of the scale, if the water is too alkaline, scale can form in the plumbing, equipment and on the pool tiles and walls.


Total Alkalinity: The ability of water to resist pH changes. When in the ideal range, sanitizer efficiency is maximized. When alkalinity is low, it is harder to control the pH; when high, water tends to look cloudy.

It is important to adjust the alkalinity before adding chemicals to adjust the pH. Sodium Bicarbonate will raise alkalinity with little effect on the pH. However, Muriatic Acid will lower total alkalinity.


Chlorine: There are several types of chlorine in the pool water: free chlorine - chlorine available for use, combined chlorine - current in use chlorine, and total chlorine - overall total. Free and combined Chlorine are both readily able to sanitize.

C&V Wetworks uses a Taylor brand professional pool and spa test kit, that includes reagents to test for the combined chlorine.


The type of Chlorine used in pools varies greatly, ranging from Liquid Chlorine, Tablets, Calcium Hypochlorite, Lithium Hypochlorite, Dichlor, or Trichlor.

Swimming pools may also have Bromine or a salt system (to create chlorine from the salt), to sanitize the pool water. Bromine's ideal ppm is the same as Chlorine, and the salt level is ideal at 3400ppm, but can range from 2800 - 3800 ppm.


Calcium Hardness: The measurement of the amount of calcium, along with other metals, that are present in the water. A low level tends to be aggressive, causing equipment corrosion and etching in the plaster. A high level typically produces cloudy water and scaling.

The most common problem with calcium hardness is that it is too high, so to lower the level, the pool can be partially drained and refilled - taking into account the source of the refill water. There are products on the market to lower calcium hardness, most contain phosphates that will join to the calcium and create a powder that collects at the bottom of the pool to then be vacuumed out.


For more in depth chemistry testing, also consider phosphate levels, total dissolved solids, and stabilizer levels.

It is important to test your pool water on a regular basis. Remember to adjust alkalinity before adjusting pH. After adding chemicals to adjust the chemistry, allow at least 4 hours of circulation before re-testing. It will not be effective to add too many chemicals at once. Please be cautious and read complete safety information and instructions for the chemicals you purchase and use for your swimming pool needs.

Chemical balancing is a vast topic and may have your head spinning trying to understand. If you are overwhelmed or simply don't have the time, leave it to the professionals. The employees at C&V Wetworks are certified service technicians and attend classes and trainings to understand chemical testing and balancing. It is our goal to ensure every customer receives quality service and a clear pool to enjoy all summer long!

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