With the continuous development of the swimming pool industry, sodium dichloroisocyanurate (SDIC) has become one of the commonly used chemicals in swimming pool water treatment due to its efficient disinfection effect and relatively stable performance. However, how to scientifically and reasonably calculate the dosage of sodium dichloroisocyanurate is a professional skill that every swimming pool manager needs to master.
Basic characteristics of sodium dichloroisocyanurate
Sodium dichloroisocyanurate is a chlorine-containing disinfectant. The main ingredient is sodium dichloroisocyanurate, which usually contains about 55%-60% effective chlorine. After dissolving in water, hypochlorous acid (HOCl) is released. This active ingredient has a broad-spectrum and efficient bactericidal effect. Its advantages include:
1. Fast dissolution rate: convenient for rapid adjustment of swimming pool water quality.
2. Versatility: not only can sterilize, but also inhibit algae growth and decompose organic pollutants.
3. Wide range of applications: suitable for different types of swimming pools, including home swimming pools and public swimming pools.
In order to ensure the use effect, the dosage needs to be calculated according to the specific conditions of the swimming pool.
Key factors for calculating dosage
In actual use, the dosage of sodium dichloroisocyanurate will be affected by multiple factors, including:
1. The volume of the swimming pool
The volume of the swimming pool is the basic data for determining the dosage.
- Volume calculation formula (unit: cubic meter, m³):
- Rectangular swimming pool: length × width × depth
- Circular swimming pool: 3× radius² × depth
- Irregular swimming pool: The swimming pool can be decomposed into regular shapes and summed, or refer to the volume data provided by the swimming pool design drawings.
2. Current water quality
Free chlorine level: The free chlorine level in the swimming pool water is the key to determining the amount of supplementation. Use special swimming pool test strips or a free chlorine analyzer/senor for rapid detection.
Combined chlorine level: If the combined chlorine level is greater than 0.4 ppm, shock treatment is needed first.(…)
pH value: The pH value will affect the effectiveness of the disinfectant. Generally, the disinfection effect is best when the pH value is between 7.2-7.8.
3. The effective chlorine content of sodium dichloroisocyanurate is usually 55%-60%, which needs to be calculated according to the chlorine content marked on the specific product.
4. Purpose of addition
Daily maintenance:
For daily maintenance, keep the chlorine content in the swimming pool water stable, prevent the growth of bacteria and algae, and maintain the water quality clean.
Dissolve SDIC granules in clean water (avoid directly sprinkling into the swimming pool to prevent bleaching the pool wall). Pour evenly into the swimming pool, or add through the circulation system. Ensure that the residual chlorine concentration of the swimming pool water is maintained at 1-3 ppm.
Shock:
SDIC is used for swimming pool shock. It is necessary to quickly increase the chlorine concentration in the water to remove organic pollution, bacteria, viruses and algae. 10-15 grams of SDIC is added per cubic meter of water to quickly increase the chlorine content to 8-10 ppm. It is usually used in the following situations:
The pool water is cloudy or has a pungent odor.
After a large number of swimmers use it.
After heavy rainfall or when the total chlorine is found to be higher than the allowed upper limit.
Calculation method of dosage of sodium dichloroisocyanurate
Basic calculation formula
Dosage = swimming pool volume × target concentration adjustment ÷ effective chlorine content
- Swimming pool volume: in cubic meters (m³).
- Target concentration adjustment: the difference between the target residual chlorine concentration to be achieved and the current residual chlorine concentration, in milligrams per liter (mg/L), which is equal to ppm.
- Effective chlorine content: the effective chlorine ratio of sodium dichloroisocyanurate, usually 0.55, 0.56 or 0.60.
Example calculation
Assuming a 200 cubic meter swimming pool, the current residual chlorine concentration is 0.3 mg/L, the target residual chlorine concentration is 1.0 mg/L, and the effective chlorine content of sodium dichloroisocyanurate is 55%.
1. Calculate the target concentration adjustment amount
Target concentration adjustment amount = 1.0 – 0.3 = 0.7 mg/L
2. Calculate the dosage by using the formula
Dosage = 200 × 0.7 ÷ 0.55 = 254.55 g
Therefore, about 255 g of sodium dichloroisocyanurate needs to be added.
Dosage techniques and precautions
Dosage after dissolution
It is recommended to dissolve sodium dichloroisocyanurate in clean water first, and then sprinkle it evenly around the swimming pool. This can effectively prevent particles from directly depositing on the bottom of the pool and causing unnecessary troubles.
Avoid excessive dosing
Although sodium dichloroisocyanurate is a highly effective disinfectant, excessive dosing will result in too high residual chlorine level in the swimming pool water, which may cause skin or eye irritation to swimmers and corrode swimming pool equipment.
Combined with regular testing
After each addition, the test tool should be used to test the pool water quality in time to ensure that the actual residual chlorine concentration is consistent with the target value.
Combined with other water treatment products
If the pool water quality is poor (for example, the water is turbid and has an odor), other chemicals such as flocculants and pH regulators can be used in combination to improve the comprehensive water quality treatment effect.
FAQ
1. Why does the dosage of sodium dichloroisocyanurate need to be adjusted?
The frequency of use, water temperature and pollution source of different swimming pools will cause the residual chlorine consumption rate to change, so the dosage needs to be flexibly adjusted according to the actual situation.
2. How to reduce the irritating odor that may be generated after addition?
Excess hypochlorous acid can be avoided by evenly pouring the SDIC solution and keeping the pump running. Do not storage the prepared solution.
3. Is it necessary to add it every day?
Generally speaking, home swimming pools are tested 1-2 times a day and topped up as needed. Public swimming pools are frequently used, so it is recommended to test them multiple times a day and adjust the dosage in a timely manner.
As the main product for swimming pool disinfection, accurate calculation of the dosage of sodium dichloroisocyanurate is crucial to maintaining the water quality of the swimming pool. In operation, the dosage should be scientifically calculated based on the actual situation of the swimming pool, and the principle of adding in batches and dissolving first and then adding should be followed. At the same time, the water quality should be tested regularly to ensure the durability and stability of the disinfection effect.
If you encounter problems in actual use, you can always consult a professional swimming pool chemical supplier for targeted suggestions.
Post time: Nov-27-2024