Pool Water in Light Green or Teal: To double shock, add 2 pounds for every 10,000 gallons of water. For example, if your pool has 20,000 gallons of water, you will add 4 pounds of shock. Pool Water in Dark Green or Blue: To double shock, add 3 pounds for every 10,000 gallons of water.
The amount you add should be measured when you buy it and written on the bottle. However, most people only use half as much as what is written on the bottle because it hurts their pools if they use more than that.
Shock is used to "jump-start" the chlorine process so that it starts faster once you add the chlorine tablets. Too much shock can cause damage to your filtration system. Always follow the instructions on your package of shock water carefully.
Typically, one pound of granular shock is required for every 10,000 to 13,500 gallons of pool water. But because particle sizes vary, it's best to follow manufacturer instructions that usually include a concentration rate for your specific brand of chlorine. Chlorine kills algae when it reacts with their nutrients (mainly nitrogen) and removes them as inert by-products of oxygen consumption.
Algae can grow in any amount of water that is exposed to sunlight and carbon dioxide. The more light and air there are, the faster they will grow. Algae also needs nitrogen and phosphorus nutrients to produce seeds that will repeat the cycle. These seeds are called "zoochory" and can be blown by wind or water carried by animals. Animals' urine contains nitrogen and phosphorus salts that help algae growth. Seeds from algae can float on the surface of the water and be ingested by birds or other animals who then consume them. This is why it is important to keep your pool clean!
Algae grows in many different colors and shapes but most often it is green because it uses the same nutrients as plants. However, red algae takes up hydrogen ions from water molecules and stops them from reacting with chlorine, while blue-green algae absorbs both hydrogen ions and oxygen molecules.
Pour 1 gallon of liquid shock per 5000 gallons of pool water into a skimmer while the filter is running (liquid shock may be purchased separately or included with a new pool kit). Granular shock can be used in place of liquid shock. Follow the label's instructions. Use caution not to get any liquid shock on yourself or your clothes, as it will cause skin irritation.
Shocking creates a controlled amount of oxidation that kills algae and other organisms that could otherwise harm swimmers. The process also removes some undesirable chemicals such as chlorine from the pool. Oxidation is only one part of the process by which pools are cleaned. Other factors include filtration, chemical addition, and natural decay. Shock treatment should not replace these other methods of pool care.
People who are sensitive to chlorine should not be exposed to large amounts of it for long periods of time. This is especially true if they have asthma or another respiratory condition. Chlorine itself is not harmful, but it does react with other substances that can be found in water sources such as minerals or organic material. When this occurs, chlorine atoms are given new properties that can cause problems for people with respiratory ailments. For this reason, it is important not to expose sensitive individuals to high levels of chlorine for long periods of time.
Shock treatment involves the introduction of approximately 5 milliliters (1/4 teaspoon) of available chlorine into each thousand gallons of pool water.
Once the pH and alkalinity are stable, add shock to the pool. For the amount of gallons of water in your pool, follow the directions on the back of the shock container. Check the chlorine level in your pool to verify you've applied enough shock. The concentration should be between 1 and 3 ppm. If it's not, increase the dosage until it is.
Shock can be harmful if not used properly or not at all. Follow these steps to ensure a safe treatment:
Remove all objects from within six inches of the edge of the pool. This includes any toys, plants, or other items that may have been floating around in the pool.
Mix equal parts chlorine bleach and shock before adding to pool. Wear protective clothing and eye protection when working with chemicals.
Have a senior family member or friend keep an eye on little ones while you're swimming. Older children should be able to help their younger peers by keeping an eye out for signs of distress or panic during and after the rescue swim.
If you are using a portable pump-style chiller, make sure it is operating correctly. Pump motors can fail for many reasons, including damage to the wiring at the wall outlet. Test the voltage at the poolside outlet by plugging a lamp into it. If the voltage is less than 10 volts, contact an electrical contractor immediately.
The sort of shock you should employ will depend on the chemistry of your water and the reason you're shocking. If the water is green, use a cal-hypo shock. If you're shocking as part of your weekly pool care and your pool appears clean, you can use sodium dichlor, potassium monopersulfate, or sodium hypochlorite. All of these are chlorine compounds.
If the water has the color of old milk, use calcium hypochlorite (cal-hypo) as a shock agent. This is the most effective way to shock an acid pool. If the water is mildly alkaline, use potassium dichromate or sodium dichromate. These are redox agents that will reduce the pH of the water by releasing oxygen during the oxidation process. Finally, if the water is very alkaline, use ammonium hydroxide. This is a strong base that will lower the pH of the water by absorbing hydrogen ions.
All chemical pool shocks have one thing in common: They must be added to the pool immediately after use. Do not allow them to sit in the container or they will lose their effectiveness.
The best time to shock your pool is while it's still empty. Use a sanitary bucket to collect any debris that may come out of the dispenser, and then pour the contents into another empty tank of equal size. Swish the solution around to remove any residue from the pump and filter, and then drain the bucket.