Pool water preparation. Chemistry for the pool.

To ensure that swimming in the pool brings you only pleasure and good mood, and taking care of it does not cause much trouble , you need to know how the proper preparation of water and the pool bowl itself affects the safe and pleasant adoption of water procedures.

The water treatment of public pools is regulated by DIN 196 regulations 43-1:1997-04, as well as GOST 53491.1 and GOST 53491.2.
A home or private pool is intended for bathing members of the same family and their guests. Therefore, the water treatment of a private pool has a number of differences from the water treatment of public pools.

How to purify pool water?

WATER PREPARATION IN THE HOME POOL, MAIN STAGES:

• Water pH control and adjustment
• Disinfection with chlorine-containing preparations and (or) active oxygen
• Algaecide treatment to kill algae
• Water turbidity removal or coagulation</ span>
• Regular maintenance of the pool with the help of technology and mechanical means (filtration system, water circulation, cleaning of the walls and the bottom of the pool from carbonate deposits, etc.)

1. Monitoring and adjusting the pH of water

What is the pH of water? The pH level is an indicator of the acidity or alkalinity of water, depending on the indicator from 1 to 12. The ideal pH value of fresh water in accordance with DIN 196 43-1:1997-04 is from 6.5 to 7.6, marine from 6.5 to 7.8 max. And in accordance with GOST 53491.1, this is an indicator of 7.2-7.6 pH units.

Why is it important to know the pH of pool water? This is the main indicator of the “character” of your pool water. If the water in the pool is alkaline (with a pH value above 7.6), turbidity of the water may occur, the appearance of lime sediment, and the activity of disinfectants will decrease. If the water is acidic (with a pH value below 7 units), then such water may irritate the human mucosa and quickly wear out the metal parts of the equipment and the pool tiling.

Depending on the pH value, further actions for water treatment are determined, so this stage is a priority.

How to check the water in the pool.

The pH level is determined using pH test strips or drops.
In addition, the pH level can be lowered or raised to the optimum level using pH plus preparations in the proportion of 50 grams per 10 cubic meters of water< /strong> and pH minus from Novokhim Company.

PH lowering agent (granules)< /span>dosage 15g per 1m3 to lower the pH level by 0.2. Requires pre-dissolution. Suitable for applications with various disinfectants (chlorine-based and hydrogen), for tap and well water.

PH-lowering agent based on hydrochloric acid 13% (liquid)dosage 100g per 1m 3 1m3 to lower the pH by 0.2. Suitable for use with chlorine-based disinfectants, tap water and well water.

PH lowering agent based on sulfuric acid 43% (liquid) dosage 45g per 1m 3 1m3 to lower the pH by 0.2. Suitable for use with various disinfectants (chlorine-based and hydrogen), for tap water.

However, it should be noted that in accordance with the “Public regulations for the treatment of water in swimming and bathing pools of all types and purposes” for 2018, The Association of Pools and Spas of Ukraine does not recommend lowering the pH with hydrochloric acid in order to avoid water saturation with chlorides, increased consumption of disinfectants and damage to equipment.

2. Disinfection of water with sodium hypochlorite and (or) hydrogen peroxide.

An essential stage of water disinfection from harmful microorganisms for safe and healthy bathing.

How to disinfect pool water?

Today, there are two main means for water disinfection – chlorine and active oxygen or hydrogen peroxide< /a>. It should be said that in accordance with the normative documents DIN 196 43-1: 1997-04 and GOST 53491.1, water in public pools should be disinfected exclusively with sodium hypochlorite. In the home pool, disinfection with hydrogen peroxide is allowed with periodic shock chlorination at the beginning of the season and during the conservation of the pool for the winter period, and also, depending on operational pollution, during the season.

When disinfecting a pool with sodium hypochlorite it is necessary to measure the level of free chlorine in the water, it must be in the range of from 0.3 to 0.6 mg /l (DIN 196 43-1:1997-04) .

For shock or impact chlorination, the concentration of free chlorine should be based on 2mg/ l. Measurements of free chlorine in water are carried out weekly using a hand-held tester or test kits.

You can calculate the required amount of hypochlorite by formula                                                               >< /

Based on the content of active chlorine in sodium hypochlorite 20%.</span >

1. Find out how much chlorine is in 1 liter of hypochlorite: 1000*0.2=200g

2. We calculate the required amount of hypochlorite for a pool of 20 cubic meters at the selected concentration of active chlorine concentration of 0.6 mg/l:selected conc. Active chlorine*volume of the pool/chlorine content in 1l hypochlorite (0.6*20/200 = 0.06) Total: need 60gr. sodium hypochlorite with an active chlorine concentration of 20% for disinfection of a pool of 20 cubic meters.

Important! If the chlorine-based disinfectant is applied correctly , then the annoying smell of chlorine in the pool is absent.

If there is an unpleasant smell, then this is a consequence of the interaction of active chlorine with organic matter in the polluted pool water. A chemical reaction occurs, as a result of which chloramines or combined chlorine are formed, which are the cause of an unpleasant odor. Such a chlorine odor can be removed by shock chlorination or using a UF lamp with a wavelength of at least 250 nanometers. You can also call for a water change.

Also, you can chlorinate your water with the handy chlorine tablets< /span>. Disinfection of water with the help of such tablets is carried out at the rate of: 200 grams of a tablet per 20 cubic meters of water. A chlorine tablet is placed in a skimmer and dissolves over the course of a week, destroying harmful microorganisms.

How to clarify and disinfect pool water with hydrogen peroxide?

Hydrogen peroxide or active oxygen It is odorless and has the ability not only to disinfect, but also to clarify water, this is its main advantage over chlorine.

Water disinfection with hydrogen peroxide at a concentration of 35% should be done the first time at the rate of 700 grams per 1 cube of water, subsequent processing is carried out at the rate of 200-300 grams per cube. The frequency of disinfection varies depending on the frequency of bathing, pollution of the pool and weather conditions. On average, the result lasts up to 3-4 weeks.
To avoid harmful effects on sensitive skin, products for disinfection of water in the pool is recommended to alternate.

The liquid disinfectant is added to the pool by distributing it evenly over the surface of the water and then mixed with a circulation pump.
< strong>After disinfection with any of these preparations, swimming is allowed only after 12 hours.

3. Killing algae with an algicide.

Flower water in the pool what to do?

Treatment of pool water with an algaecide is an important step, as it prevents algae formation and enhances the effect of the disinfectant. The addition of an algaecide does not preclude the disinfection of water with sodium hypochlorite or peroxide, but it can reduce the frequency of their consumption.

4. Is your pool water cloudy?

Using a coagulant or flocculant to remove turbidity in pool water.
In the water of any swimming pool there are suspended particles or small particles, sometimes difficult to see with the naked eye. Such particles are not able to trap the usual sand filter. To eliminate them, it is necessary to add a coagulant to the water, a substance that is able to combine the smallest suspended particles into larger flakes. These are then filtered or precipitated to the bottom of the pool. It is then also removed by means of a bottom hoover and a filter unit.

The use of Liquid Floc from Novohim Company will make the water in your swimming pool transparent and eliminate turbidity.

Liquid Floc is added to the pool at the rate of 50 grams per cube of water.

After adding any chemical substance to the pool it is recommended to switch on long circulation (min. 5-fold water exchange) for qualitative mixing of the preparation in the water of your pool or to mix the water by other mechanical means.

5. Pool maintenance.

It should be remembered that the use of chemical preparations for pool water treatment does not exclude other mechanical maintenance. The main stages of such maintenance are:

1.Removing leaves and other contaminants from the water surface with a net

2.Cleaning of the skimmer and pump strainers

3.Cleaning the bottom and walls of the pool bowl from salt deposits, algae and other deposits using a brush and a bottom hoover.

4.Only specialised pool maintenance products should be used for cleaning.

5.Periodically rinse the sand filter and replace as necessary

6.Conduct regular measurements of basic pool water quality parameters (pH, chlorine, total and carbonate hardness).

The average total water hardness (calcium salt content) ranges from 1.44 to 2.16 millimoles per litre (mmol/l). If this value rises to 3 mmol/l or more, water hardness reducing agents should be used, otherwise there is a risk of difficult to remove deposits on the pool walls and rapid water turbidity.

What is carbonate hardness?

There is also carbonate hardness, which indicates the level of calcium and magnesium carbonates and hydrocarbonates in the water. Underestimated carbonate hardness can be the cause of pH spikes and difficulties in adjusting the pH level. To avoid this consequence it is necessary to maintain carbonate hardness at a level not lower than 0.7 mmol/l using a pH stabiliser.

It is recommended to use tap water or tested water to fill the pool (e.g. water from wells can often contain excessive amounts of iron, which will adversely affect the pool water, giving it a brown colour).

IMPORTANT: When using chemical reagents for pool water treatment, it is necessary to take into account the characteristics and type of the pool, water composition and hardness, installed equipment, frequency of bathing and individual characteristics of the organism. All the above-mentioned norms are given as an average calculation and may be subject to adjustment.

Water treatment in the swimming pool. Problems, possible causes and methods of their elimination.

Problem	Possible cause	Method of elimination
Rusty or brown coloured water	Excess iron or manganese in the water	Adjust pH to an average of 7-7.6 units Conduct shock chlorination Check pH Add flocculant to the water Switch on continuous water circulation (min. 5 times water exchange). Apply ‘MetallStop’ from Novochem Company
Milky cloudy coloured water	Presence of tiny suspended solids in the water Total water hardness is increased	Adjust pH 7-7.6 Carry out shock chlorination Check pH Add floc to the water Switch on continuous circulation (min. 5 times water exchange). Check water hardness, adjust if necessary. Add flocculant Ensure continuous water circulation
Slimy scum on the pool walls, water green in colour	Active algae growth Lack of disinfectant and algaecide Incorrect pH level External conditions (high temperatures, large number of bathers, etc.)	Carry out mechanical cleaning with a telescopic brush Adjust pH Carry out hypochlorite shock chlorination Check pH level Add algaecide Circulate water
Irritation of the mucous membranes and skin	The pH level is too high or too low High chlorine levels in the water	Check and adjust the pH level Measure free chlorine in the water, adjust
Corrosion of metal elements of the swimming pool	Underestimated pH value of the pool water Calcium deposits	Adjust the pH level to 7-7.6 pH units with pH Plus product Ensure control of water hardness
Rough patina on the pool walls	Calcium deposits in case of high water hardness	Drain the water Use a brush and an acidic agent to remove deposits Fill the basin Carry out all stages of water treatment (p.1)
Foam formation in swimming pools with artificial currents	Use of foaming algaecide Residues of winter preservative in the water Use of kitchen cleaning agents	Ensure long-term water circulation Increase fresh water inflow Thoroughly rinse off after pool cleaning Use a non-foaming algaecide Use only specialised cleaning products