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Why You Need A Pool Test Kit?

Posted on: August 15, 2020, by Jason
pool-test-kit
pool-test-kit

In the scorching summer, everyone wants to go swimming to temporarily escape the heat of the summer. However, as the swimming pool is crowded, the water quality cannot be guaranteed. Is there any good way to test the water quality of the swimming pools? Pool test kit or pool test strips?

What items need to be tested for swimming pool water quality testing?

A. Swimming Pool Water Testing

FrequencyMeasurement parameters
Daily InspectionDisinfectants (chlorine, bromine, ozone, etc.)
PH
Water temperature
Turbidity
Weekly InspectionAlkalinity
Calcium hardness
Monthly InspectionTDS
Cyanuric acid
Sulfate
Total number of bacteria
Escherichia coli

B. Pool Water Quality

 Test ItemsLimit
1Turbidity≤1NTU
2PH7.0~7.8
3Urea≤3.5mg/L
4Total number of colonies(36 ±1 ℃,48h)≤200/mL
5Total coliform(36 ±1 ℃,24h)0/mL
6Free residual chlorine0.2~1.0mg/L
7Compound residual chlorine≤0.4mg/L
8Temperature23~30 ℃
9Total dissolved solids(TDS)≤raw water TDS+1500mg/L
10Oxidation-reduction Potential(ORP)≥650mg/L
11Cyanuric acid≤150mg/L
12Trihalomethane (THM)≤200μg/L

C. Item Interpretation

  • Turbidity
    Turbidity is the clearness of the pool water. It is an index that reflects the physical characteristics of the water quality monitoring. It can subjectively reflect the amount of suspended air pollutants in the pool water. If the turbidity of the water is too large:
    • It is difficult to see through the pool, which affects the experience feeling of the swimmers, and affects the vision of the lifeguards on the opposite shore, which is likely to cause safety accidents or delay rescue work;
    • Excessive particles may damage the swimmers’ eyes;
    • The water contains many kinds of microorganisms, which may spread diseases;
  • PH
    The PH is an index that reflects the acidity and alkalinity of water. The excessively acidic or alkaline environment of water can easily cause irritation to the eyes and facial skin of swimmers.
  • Urea
    The content of urea solution is a unique standard in swimming pool water quality standards in China. The urea solution in the water mainly comes from human sweat and secretions. The more urea solution content, the higher the pollution degree of the pool water.
  • Total number of colonies
    The number of germs is an index that evaluates the operating quality of the pool water treatment equipment system. It is an effective method to understand whether the pool water is disinfected and sterilized, and it is also an important index for the filtration rate. When the disinfection fails and the filter cannot meet the working requirements, especially the bacteria multiply in the activated carbon filter, so the water quality of the piping system and the balance tank deteriorates, unconventional detection of Staphylococcus aureus must be carried out.
  • Total coliform
    If there are numerous E. coli groups in the pool water, it means that the pool water has been polluted by human feces.
  • Free residual chlorine
    The requirement of mine acid residual chlorine is to ensure the continuous disinfection and sterilization ability of the swimming pool water, preventing the reproduction of residual germs in the water and the adverse effects of infection and the sudden increase of the pool water load.
  • Compound residual chlorine
    The chemical residual chlorine refers to the solubility of chlorine disinfectant in the pool water under the combined condition of chloramine and ammonia. The chemical residual chlorine is very irritating and can cause nasal mucositis and laryngitis. Therefore, it is necessary to limit the solubility of chemical residual chlorine. The ideal solubility should be a small half or less of the mine acid residual chlorine.
  • Water temperature
    The comfortable temperature should be 23-30℃. Different swimming pools have different water temperatures. If the temperature is too low or too high, the human body will easily feel uncomfortable.
  • Total Dissolved Solids (TDS)
    Total Dissolved Solids refers to the sum of all inorganic metals, salts, and organic substances dissolved in water, but does not include substances suspended in water. It is an index to check whether the pool water needs to be dissolved or refreshed. If there are excessive total dissolved solids in the pool water:
    • The pool water will become turbid;
    • The chlorine is ineffective;
    • It will prevent the pool water from discoloration;
    • The cycle time of the filtration system will be shortened;
    • The water will produce odor.
      The effect of low total dissolved solids in pool water:
    • Reduce the effectiveness of the filtration system;
    • Make the water appear slightly grass green. This inspection item is an unconventional inspection item.
  • Oxidation-Reduction Potential (ORP)
    This item is an index indicating the ability of disinfectant to kill bacteria. It is an index of the International Union of Drinking Water Standards. ORP is a measure of the air oxidation capacity of disinfectant, not the content of disinfectant. Practical experience shows that as long as the PH of the pool water is within the standard range and the ORP value is higher than 600mV, then the amount of pathogens in the pool water should be within the reasonable range.
  • Cyanuric acid:
    Cyanuric acid is the collective name of sodium dichloroisocyanurate and sodium trichloroisocyanurate. It is an organic disinfectant that will continue to accumulate in the pool water, but will be converted by sunlight when the amount is too small, and will easily affect disinfection when there’s too much of it. Therefore, when using these two disinfectants, cyanuric acid must be detected and controlled.
  • Trihalomethane (THM)
    Trihalomethane is a by-product of the use of chlorine for disinfection and sterilization. It contains uncertain substances that are pathogenic, teratogenic and carcinogenic. Therefore, the content of trihalomethane in water quality monitoring should not be underestimated.

Test Methods 

The most commonly used methods for testing swimming pool water are pool test strip and pool test kit. Both are rapid test format, easy to use, few procedures perform, fast to results.

1. Pool test strip

Swimming pool test strip is a quick and convenient option for swimming pool water testing, which can be used to measure total hardness, total chlorine, free chlorine, PH, total alkalinity and stability. Many pool owners find test strips economical, easy to use, and easy to read.
Pros:

  • Fast
  • Easy to use and read
  • Cheap
  • The best choice for daily pool chemical analysis

Cons:

  • Fewer test functions
  • Lower accuracy
  • Hands must be completely dry when the test strip is removed

How To Use Pool Test Strips?

  • Use clean, dry hands to remove a test strip from the bottle and close it tightly
  • Immerse the test strip in the pool, away from the sprinkler and hold the elbow depth for 15 seconds.
  • Remove the test strip from the water and compare the results with the chart provided in the package.

2. Pool test kit

There are two kinds of pool test kit: DPD test and OTO-Phenol test. The DPD test usually measures chlorine, pH, alkalinity, stabilizers and hardness. The OTO-Phenol kit tests chlorine and PH. The use of pool test kits can be more time-consuming, but they are generally more accurate than test strips.
Pros:

  • The most accurate type of water quality test. Liquid DPD reagent is best for testing the chlorine content in swimming pools.
  • More items can be tested
  • Suitable for swimming pool professionals and health authorities

Cons:

  • Expensive
  • The testing process may take longer and be more complex.
  • The reagent bottle must be placed vertically to ensure uniform droplet size and must be counted when adding droplets slowly.
  • Operators are prone to errors during use

How To Use Pool Test Kit?

  • Please remove the tube cap and rinse the tube before use
  • Fill the pipe with swimming pool water up to the indicated line. Make sure to place the sample away from the nozzle and hold elbow depth.
  • Please follow the package instructions, and then drop appropriate amount of reagent solution into the water sample.
  • Cap the tube and shake it gently to mix the solution thoroughly.
  • Compare the color of the water with the chart provided in the test kit.

High quality pool kits should have simpler and easier operation, shorter waiting time, more accurate results, and most importantly, the price is so favorable that it can be widely used by families at home! Where to buy pool test kit? It’s easy to purchase best pool test kit in online platforms: Amazon, Ebay or Shopify with “best pool test kit for saltwater pool”, there are hundreds brands alterative. AquaCheck, Taylor pool test kit, PoolMaster, Milliard, etc.

 Pollution Sources

  1. Human body dirt, bacteria, viruses, urea, etc.
  2. Dandruff
  3. Cosmetics
  4. Human secretions: oil, sweat, oral and nasal secretions
  5. Other pollutants: dust, leaves, small insects
  6. Bacteria and algae growing in the pool
  7. Pollution caused by the biofilm in the balance tank, filter medium, and inner wall of the pipe valve.

How to do the daily work of swimming pool disinfection?

  1. Open-air swimming pool: In summer, the sun source is strong, and the disinfectant in the pool water is decomposed by light. The stronger the sun source, the faster the decomposition rate. It is recommended to shade the pool properly and use TCCA disinfectant with stronger chlorine stability.
  2. Deep well water swimming pool: It is recommended to increase the iron and manganese removal process, otherwise the color of the water cannot be blue.
  3. Tourists management: There are more people in the swimming pool in summer, and the secretions of the human body and the bacteria carried will reduce the residual chlorine. It is recommended to strengthen the sanitation awareness of swimmers and force showers before going down the pool.
  4. Seasonal factors: outdoor swimming pools are needed to add algaecides during the summer rainy season.

FAQ about swimming pool water quality testing

1. Why is the residual chlorine index qualified, but the microbiological index exceeds the standard?

  1. There are two independent indicators for the residual indicator and the microbiological indicator. Whether the residual chlorine is qualified and the microbiological indicator is not necessarily related. Conversely, whether the microbiological index is qualified is also not necessarily related to whether the residual chlorine is qualified.
  2. The disinfection effect of disinfectant is not only related to the dosage of disinfectant, but also related to the turbidity and PH of the pool water. The greater the turbidity, the worse the disinfection effect. The PH should also be adjusted to the optimum range suitable for disinfection (the optimum PH range for chlorine disinfection is 6.5-7.5). Otherwise, even if the residual chlorine index is qualified, the microbiological index may still exceed the standard.
  3. The unevenness of the pool water is also one of the reasons. The samples for residual chlorine detection and microbial detection should be sampled at the same place (the same water sample) at the same time to eliminate the source of difference to the greatest extent.

2. Why are the swimming pool self-inspection results inconsistent with the inspection results of the supervision department?

  1. System error: Different models, brands, and different operators may have different results when testing. If the difference is small, it is normal.
  2. When the difference is large, it should be analyzed scientifically to find out the reason.

3. What should be paid attention to when treating the first pool of water (making water)?

  1. For swimming pools that have not been opened for a long time, it is recommended to clean the pool pipes and pool filters with pipe cleaners and filter cleaners before cleaning the pool body to remove grease in the pipes and filters.
  2. After the pool body is cleaned, it is recommended to use copper sulfate to spray the pool body and the wall with a solubility of 1.5mg/L or 3mg/L chlorine with a sprayer, and then dry it for one to two days and then fill it with water, which can extend the time to prevent algae growth.
  3. At the beginning of water injection, users with slow water injection speed can add a small amount of disinfectant when the pool is filled one-third to prevent the algae.
  4. The downstream swimming pool can be cyclically disinfected when the water in the swimming pool is full to the point of return, while the counter-current type needs water to circulate after filling. Note: Regardless of upstream or downstream flow, the filter must be backwashed before opening the cycle. (Avoid discharging the foul water accumulated in the filter for a long time into the swimming pool)
  5. When adding disinfectant to the first pool of water, it is not advisable to add a large amount of disinfectant at one time, which will easily cause the pool water to change color. It is recommended to add a small amount for multiple times. The water contains mineral elements, which are oxidized and discolored. (Tap water iron pipes, secondary water supply pollution, etc. may cause the water to contain mineral elements; deep underground well water is more likely to contain mineral elements).

4. The dosage of chlorine disinfectant has been increased. Why is there no corresponding increase when detecting residual chlorine?

  1. The high ammonia nitrogen in the water causes the added disinfectant to preferentially form compound chlorine with the ammonia nitrogen, which consumes a large amount of chlorine without increasing the amount of residual chlorine. At this time, as long as you pay attention to the compound chlorine, if the test result meets the standard, the disinfection effect can also be ensured;
  2. The high ammonia nitrogen in the water causes the added disinfectant to preferentially form compound chlorine with the ammonia nitrogen, which consumes a large amount of chlorine without increasing the amount of residual chlorine. At this time, as long as you pay attention to the compound chlorine, if the test result meets the standard, the disinfection effect can also be ensured;

Conclusion:

Pool test strips and pool test kit are both widely used in swimming pool water quality testing. But if you want more accurate and comprehensive test results, it is recommended to choose pool test kits.

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