Swimming pool water quality test

- Aug 06, 2020-

The main products of analytical pool water chemistry are test strips, 4 in 1 test kits and water quality test instruments. Everyone can provide reliable readings of chemical levels in swimming pool water, and most include step-by-step instructions that are simple for first-time swimming pool owners.


Method for balancing swimming pool water quality parameters


The four chemical levels that are critical to healthy water quality are free chlorine, calcium hardness, pH and total alkalinity. Except for cyanuric acid, these compounds work together and each is at the right level to help provide sparkling swim-ready water.


If the water quality test reveals that one or more chemicals are too high or too low, measures must be taken. With the water reading, you will know to add products such as chlorine, hydrochloric acid, sodium bicarbonate, or other pool treatments.

Free chlorine

Whether in tablet, liquid or powder form, the chlorine in the pool will kill a range of viruses, bacteria and organic matter. Chlorine disinfects water to remove most pathogens that may harm swimmers. The free chlorine level refers to the "fresh" chlorine in the pool water that has not reacted with any contaminants. Too much or too little of this chemical can cause potential harm to swimmers and pool equipment. Without enough free chlorine to attack the invading pollutants, swimming pool water is susceptible to various adverse effects.


Algae may grow, blur the water, and become green and slimy along the floor and walls of the pool. Unwanted green visitors can also use certain types of swimming pool filters to coat the ink cartridges, which requires more frequent cleaning, thereby shortening the life of the product.

multiple water test meter

If there is not enough chlorine, the appearance of the water may become turbid by organic matter blown in by the wind and organic matter brought in by swimmers, such as sweat, makeup, body oil and tanning oil.


To make matters worse, too little chlorine poses a safety hazard to water-borne diseases! When swimmers (including pets) introduce biological substances, there is not enough disinfectant to defeat pathogens. As a result, the chances of infectious microorganisms spreading and disease increase.


On the other hand, the high content of free chlorine causes its problems. Too much will stab swimmers’ eyes and irritate their skin. Increased levels of this chemical can cause severe, bleach-like odors, which are very detrimental to inhalation and irritation to the lungs of swimmers.


Swimming pools need enough free chlorine to kill unwanted pathogens and pollutants, but it will not cause harmful effects on swimming pool users. It all depends on reaching a balance of 1.5 to 2.5 ppm. Note: Swimming pools using ozone systems and/or UV disinfection sterilizers require only 0.5 to 1 ppm of chlorine.

pH value


The pH value represents the total acidity of the pool water. It is measured on a scale of 1 to 14: 1 to 6, which indicates how much acidity is; 8 to 14 indicate alkalinity. In the middle of 7.3-7.7ppm is neutral, where should the pool water be.


If the pH is too low, the water can irritate swimmers' eyes and skin. Low pH can also damage swimming pool equipment: ladders, railings, and other accessories with metal parts may start to corrode, and parts of pool heaters may also corrode.


If the pH is too high, it may reduce the effectiveness of free chlorine in the water, which may cause unsanitary swimming conditions. The high pH range may cause the water to become turbid, like low pH water, it may cause itching of the skin and burning of the eyes.

multiple water tester

If the alkalinity and calcium hardness levels in the pool also increase, the resulting combination with a high pH means other troubles. The unbalanced chemical triad may cause the skimmer of the swimming pool, the inner surface, various equipment accessories and some automatic swimming pool cleaners to foul.

Total alkalinity


Total alkalinity (TA) refers to the total amount of alkaline substances present. In order for TA to be effective in the pool, the level should be between 90 and 120 ppm.


Alkalinity is important to pool water chemistry because it has an important effect on maintaining a neutral pH. If the TA level is too high or too low, the pH value may fluctuate; usually if the TA level is closed, the pH will also be closed.


Low TA is problematic. The consequences of anyone using the swimming pool include burning eyes and having to swim in dark water.


The swimming pool has a major impact. The water becomes "active" and attacks the metal parts of swimming pool fittings and equipment such as railings, ladders and heat exchangers in heating systems.


On the other hand, too high TA content in water can irritate swimmers' skin. It also reduces the effectiveness of free chlorine, can stimulate the growth of algae and bacteria, and the problem of low chlorine content.

Calcium hardness

Calcium hardness measures the hardness level of pool water and indicates whether the water is too hard, too soft or just right.


If the hardness level is too low, this means that the water-soft plaster bears the brunt. When the mineral seeps out of the material, the previously smooth internal surface is etched and filled with unsightly pitting.

multiple parameter water quality test equipment


Of course, if the calcium hardness is too high, it will cause another series of problems. Ugly calcium deposits will form on the internal surface of the pool, resulting in gray, white or brown spots inside the pool.


If pH and alkalinity rise like calcium, the news is particularly bad. Scale can accumulate and severely damage the pool pumps, heaters and components in the DE or cartridge filter.


Unchecked scaling in extreme cases may require expensive, tedious effort that any pool owner wants to avoid: exhausting the pool. This is what it takes to perform and pickle it to remove all mineral deposits.


Don't let this happen. To prevent out-of-control calcium and related complications, check the calcium level in the range of 200-400ppm