The only way to cure chlorine demand is to give your pool the chlorine that it needs through consistently shock treatments. A general rule to follow is to use 3 pounds of calcium hypochlorite pool shock for every 10,000 gallons of pool water. This may vary depending on the degree of chlorine demand that your pool has.
Continue shocking and retesting every three to four hours until you can maintain a 3 ppm free chlorine reading for 24 hours. Drain 2.5 feet of water and dilute with fresh water to eliminate some of the demand.
The consistent inability to maintain chlorine levels is also called “chlorine demand” and is most often caused by a high level of inorganic and organic contaminants in the water. Those contaminants force the chlorine to work extremely hard to oxidize them, leaving little chlorine to protect swimmers.
Why can't I get a Chlorine reading? If you test your pool water and can't get a chlorine level reading at all it may be due to very high chlorine demand. High chlorine demand is the inability to keep an adequate level of chlorine in the pool water even though the water appears to be balanced and properly maintained.
If your water's pH is too high, it hinders the chlorine's ability to efficiently clean the pool. A water pH level that is too low causes the chlorine to dissipate more quickly. Therefore you'll need to add more chlorine to accomplish the task.
The fastest way to do this is by shocking your pool. But not the way you normally do. Your best bet is to triple shock it with calcium hypochlorite. To triple shock, add 3 pounds of shock per 10,000 gallons of water.
Subtract the residual chlorine (step 16) from the quantity of chlorine that was added to each bottle (step 8) to determine the chlorine demand: Cl2 Demand = Cl2 added concentration (mg/L) – Cl2 residual measured concentration (mg/L)1.
Of these, the concentration or dosage of chlorine and the chlorine contact time (the time that chlorine is allowed to react with any impurities in the water) are the most important factors.
Uses of Bleaching Powder
It is used for bleaching dirty clothes in the laundry, as a bleaching agent for cotton and linen in the textile industry. It is a strong oxidizing agent, hence used as an oxidizer in many industries. It is used as a disinfectant which is used for disinfecting water to make potable water.
Chlorine levels up to 4 milligrams per liter (mg/L or 4 parts per million (ppm)) are considered safe in drinking water . At this level, harmful health effects are unlikely to occur.
The Bottom Line about Pools and Chlorine
As mentioned above, you could probably swim in a pool without chlorine without any major health issues. However, long-term use of a pool lacking chlorinated H2O could make you sick or, at the very least, contribute to rashes and other types of skin irritation.
Can you put too much shock in a pool? SKIMMER NOTES: It's unlikely but it could happen. It would take a lot of shock to really make the water unsafe for swimming. The best way to make sure you're safe to swim is to test your pool water and make sure free chlorine levels are between 1-4ppm for healthy swimming.
Of course, too much chlorine in pool water can be dangerous. Exposure to over-chlorination can provoke asthma, lung irritation, and potentially skin and eye irritation. As well as being potentially bad for you, it's bad for your pool.
"Shocking” refers to the process of adding chlorine or non-chlorine pool chemicals to the water in order to raise the "free chlorine” level. The goal is to raise this level to a point where contaminants such as algae, chloramines and bacteria are destroyed.
In the simplest of terms, a pool conditioner or stabilizer helps your chlorine stay in the water longer. In other words, it prevents drastic chlorine loss. More specifically, it binds to chlorite ions (your free chlorine), making them impervious to the sun's rays.
Shock is chlorine, in a high dose, meant to shock your pool and raise the chlorine level quickly. Chlorine tabs (placed in a chlorinator, floater, or skimmer basket) maintain a chlorine residual in the water. You do need to use both tabs and shock.
You can “under-shock” your pool. It is important that you make sure to use the proper volume of Liquid Chlorine according to your pool's gallonage. If the situation of your pool does not significantly change within 12 to 24 hours of filtering, you can add a second dose of Liquid Chlorine.
High doses of chlorine, like pool shock, can cause temporary cloudiness as it kills contaminants. High levels of pH, alkalinity, and calcium hardness are more likely to cause cloudy water.
If your total chlorine level is high, you will use a non-chlorine shock; if it is low, you will use a chlorinated shock. As a rule, you will need to raise free chlorine to 10 times your combined chlorine to hit what is known as “break point.” Therefore, it is good to deal with combined chlorine while it is still small.
I think the answer to your question is about 3-6 days. The problem is that the chlorine that you need to keep the bacteria in check is used up more quickly as the temperature rises, the activity increases, and as sweat and other body stuff is put into the pool.
It's often recommended to shock your pool once a week. If you don't do it every week, you should at least do it every other week. This is necessary to maintain your pool's water chemistry. If you have a lot of people over in your pool or have a party, you may want to shock your pool more frequently.
Yes, boiling water for 15 minutes is one way to release all the chlorine from tap water. At room temperature, chlorine gas weighs less than air and will naturally evaporate off without boiling. Heating up water to a boil will speed up the chlorine removal process.
An affordable water filter such as TAPP Water will remove 98% of the chlorine and chloramine at the point of use and makes the tap water taste better and safer to drink.
2 ppm of Chlorine will take up to 4 and a half days or around 110 hours to evaporate from 10 gallons of standing water. Ultraviolet light, water circulation, and aeration will speed up the evaporation process dramatically. Chlorine will last between 6 and 8 minutes in 10 gallons of boiling tap water.