Use of chemical agents
The starting point is the available water, that is the water supplied in the water supply system or taken from own well. For the appropriate dosage of chemicals, we need to know the chemical composition of the water. For example, water from own well contains more calcium and iron.
In order to maintain clean water in the swimming pool, it is necessary to also have the proper pH value. The natural pH value, not irritating to mucosa of humans ranges between pH 7.2 and 7.6 and such the value is also the best for swimming pool equipment. Keeping the pH value within the proper range is a very important factor impacting the effective reactions of chlorine, the occurrence of corrosion, settling of calcareous scale and water aggressiveness. The pH value below 7.2 results in irritation of eyes, strong smell, corrosion on bathroom equipment and turbid water. The pH value above 7.6 results in irritation of eyes, increases the growth of algae, reduces the effectiveness of chlorine and results in settling of scale. For increasing or reducing the pH value, special agents are used. If it is difficult to stabilise the pH value, you most probably need to adjust the alkalinity of water, that is the amount of alkaline substances in water. In general, you should always wait some time between the adjustment and the subsequent measurement for the sake of stabilisation.
Chlorination is the most popular method of disinfecting the water in the swimming pool. This method is both effective and inexpensive, however, with some persons it may cause rash. Chlorine can be bought in liquid or granular form or in tablets. The preparations can be divided into organic and inorganic chlorine. Organic chlorine has prolonged effect, whilst inorganic chlorine has very fast effect and is often referred to as shock chlorine. Multifunctional chlorine is the combination of prolonged effect chlorine, algaecide and coagulant.
In the newly filled swimming pool, you might need chlorine stabiliser, which will protect chlorine from too fast depletion caused by sunrays and heat. Chlorine tablets are placed in the skimmer and are dosed through dissolving.
In order to protect against intensive growth of algae –n hot days or in order to replenish the amount of chlorine after heavy rain or intensive swimming – you might need shock chlorine disinfection. It is necessary in order to eliminate bacteria and algae, which would in such the case resist normal dose of chlorine. Shock supply of chlorine should be done after all swimming, with water circulation switched on. The chlorine content will be elevated immediately following the procedure, but after a few days it will start to drop. The recommended level of free chlorine (chlorine not tied (combined) by pollution) is 0.6 – 1.0 ppm or mg/l. Irritation is caused mostly by combined chlorine. Shock disinfection using chlorine reduces the content of combined chlorine. After the use of shock amount of chlorine, larger particulates can be collected through vacuuming the bottom, whilst larger ones will be trapped by the filter.
Flocculation agent is used for making the filtration process more effective. Fine particulates are caused to clump together into floc, which makes them easier to trap in the sand filter.
Algaecides are used preventively as complementation of chlorine. The early sign of growth of algae is slippery residue on the swimming pool walls and bottom. If algae have already grown, apply shock chlorine disinfection and add algaecides.
When handling the chemicals, always use the necessary protective equipment. Always adhere to the safety and dosage recommendations contained on the packaging. Add one chemical agent at a time, so that they do not react with one another in a concentrated form. Add chemicals to water and not the other way round.