Adding chlorine besides the shock can increase the chlorine content in the water which can make the entire shocking process useless. Hence, it is better if you don't use the shock and chlorine at the same time. The best time to add chlorine to the pool water is after you have shocked the pool.
You should wait one hour per pound of shock product added, and then test the water to confirm the pH and chlorine are in the proper range before letting anyone enter the pool. As a reminder, you want your pH to be between 7.2 and 7.8ppm and your free available chlorine to be 1-4ppm for safe swimming.
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. The formula for hitting breakpoint can get a little complicated, so we suggest you talk to your pool professional.
Low chlorine levels often cause green or hazy water, so if your water looks a little cloudy and you haven't shocked in a while, adding shock is the first step.
Non-chlorine is an oxidizer, meaning that it does a great job cleaning up oils and organic matter. However, it doesn't actually kill bacteria or algae—you need chlorine for that. Therefore, you always need to use non-chlorinated shock in conjunction with chlorine to keep your pool water healthy for swimming.
You cannot overshock a swimming pool or add too much. Adding too much shock or overshocking your pool will kill off algae. The negative of adding too much shock is it will upset the chemical balance of your pool.
You should never add chlorine and muriatic acid at the same time. The muriatic acid will react with the chlorine in your pool and create a deadly gas called hydrochloric acid. You need to wait for a minimum of 30 minutes, after you add the acid, before adding any chlorine to your pool.
The best time of day to shock your pool is in the evening. This is because the sun's rays can affect the effectiveness of the chlorine by dissolving it too quickly, before it has a chance to rid the pool of contaminants and clean the water.
Liquid chlorine and granular shock have the same active chemical that sanitizes your pool, what changes is the strength and the way you use it. Liquid chlorine is less costly, unstabilized and comes in liquid form. Granular shock is stabilized and comes in a solid form that dissolves in your pool.
Typically for granular shock, you'll need one pound for every 10,000 to 13,500 gallons of pool water. With over 8 million residential swimming pools across the US ranging from 5 thousand gallons to over 30 thousand gallons, the amount of shock you need to treat a swimming pool isn't a one-size-fits-all answer.
A pool filter should be run for a minimum of 6 hours after shocking a swimming pool. This is to allow the filter to clean the water and give the shock enough time to fully mix with the pool water. Running the filter after shocking for 24 hours to 7 days is necessary if the pool has a large amount of algae.
Neither will chlorination be effective with a diffuser and without a pump. The best thing to do is to apply liquid chlorine in the pool. Then, you have to circulate the pool manually with the use of a telescopic pole or paddle. This will ensure the chlorine disperse well.
Heavy shocking with granular chlorine will generally require 24-48 hours before the chlorine level has dropped to safe swimming levels (below 5 ppm). Lithium and Non-Chlorine shock labels typically allow immediate swimming, but check the package label, to be sure.
What can happen if you go into a pool too soon after it's been shocked? There are a few potential issues. "Chlorine will react with water to produce an acid," Alan says. "The effects will be different depending on whether chlorine is inhaled or whether there is skin or eye contact."
Wait times for adding pool chemicals
The wait times between adding pool chemicals is usually around 10 minutes each, as that is also sufficient time for the chemicals to mix in the water. Users also under normal conditions can swim roughly 10 minutes after adding chemicals.
In this case, you should double shock your swimming pool water. To double shock, you will need to add 2 pounds for every 10,000 gallons of water. For instance, if you pool is 20,000 gallons, you will add 4 pounds of shock.
It's pretty tough to over-shock your pool; shocking your pool two days in a row with the proper dosage for your pool volume shouldn't be a problem – and in fact, is sometimes even needed to rid your pool of algae and other contaminants.
Shocking your pool isn't necessary, although, it's not a bad idea either. If you get an extremely heavy rain fall, you could shock your pool for good measure. This will help fight off any contaminants that the rain may have brought to your 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.
In fact, never mix any type of acid with any type of chlorine either, because the fumes can be toxic and even lethal. And always add a dry chemical to water, never water to the dry chemical.
Pools can immediately turn green after shocking when they have metals like copper or iron in the water. These metals oxidize when exposed to high levels of chlorine which makes the pool water turn green. Metals in the water are caused by some algaecides and using well water.
After Shocking Your Pool
It is safe to swim once your chlorine levels are around 5 ppm or after 24 hours. It is always best to test first!
After you shock the pool — As soon as your chlorine levels reach 5 ppm or lower, it's officially safe to swim. Depending on the type of shock used, as well as the amount used, it can take anywhere from 24 hours or even up to a couple of days.
Chemicals that you add to your pool while the water is circulating don't need to be recirculated; they will stay mixed even if you don't pump the water continually. Although it's generally recommended that all the pool water undergo filtration every 24 hours, the pump does not need to run all the time.