How Long After Shocking Can I Swim..Swimming Pool Chlorine

by Carlos
(miami,florida,united states of america)

How long do I have to wait after shocking a pool so you can get in?

Thanks for the question Carlos

It's really not a matter of time, but when the pool chlorine level is down to a safe level.

This level is normally between 1.5ppm - 3.5ppm.

After shocking your pool the chlorine level will be above 10ppm - 12ppm to kill any bacteria and organic matter in the swimming pool.

With the sun and heat of Miami, you could probably swim within a couple of days because the heat will reduce the chlorine level in the pool very fast.

If you need to use the pool earlier, you can use a product called Thiosulfate, which can be found in any pool supply store.

Thiosulphate is a swimming pool chlorine neutralizer and will reduce the chlorine level very quickly.

Be sure to read the directions and take the proper precautions when adding any pool chemicals.

Have a great Summer


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Low Pool Chlorine & Stabilizer

by JIM

About low swimming pool chlorine level, stabilizer, and cyanuric acid...

My pool is 27,000 gallons. The pH level is good and the swimming pool is very clean, but I cannot keep any chlorine in pool.

The pool store told us to use stabilizer in pool, so we put it in sock and tied it to ladder as we were told to do.

They said it would take the stabilizer 2 weeks to work.

Is this true?

Every year I have same problem. Do I need to keep solar cover on?

I do have swimming pool heater and I could use some help.

Thank You

Jim G

Thanks for your question Jim

You seem to have an issue that many swimming pool owners face; a loss of pool chlorine.

The main reason that pools will lose the chlorine level quickly, even after a good pool shock, is because of low cyanuric acid (CYA).

This kind of acid is used as a stabilizer for your pool chlorine.

Chlorine Tablets

Swimming Pool Chlorine

There are basically two ways to add cyanuric acid to the pool; with chlorine tablets (Trichlor pucks or tabs) and granules (Dichlor).

Dichlor, or sodium dichloroisocyanurate, is a granular, stabilized, and fast dissolving form of pool chlorine and is often used as a pool shock.

While Dichlor does add pool chlorine it will also increase your CYA level while lowering your pool water pH level.

Take care in using Dichlor as your CYA can get out of hand very quickly.

Trichlor, or trichloroisocyanuric acid, are sold as 1" and 3" tablets or pucks that you can either put into a swimming pool floater or a chemical feeder.

When the water passes over the tablets they dissolve to increase the swimming pool chlorine and cyanuric acid level in the pool.

They will also lower the swimming pool pH levels because they tend to be on the acidic side.

The best way to test your CYA is by using the right pool water testing kit.

I've always used a Taylor Reagent FAS-DPD K 2005 or 2006 water testing kit.

Pool Water Testing Kit

These are the best and are used by most pool techs and professionals.

It does take some time to build up your pool's CYA level and is subject to a variety of changes.

Evaporation will mean adding more water which can reduce the amount of cyanuric acid in the swimming pool.

About 2 weeks for the CYA to get between 20ppm - 40ppm is not far off. Keep your chlorine level between 1.5ppm - 3.5ppm and you'll be fine.

You can keep on solar cover on the swimming pool as this will not only help in heating the pool quicker, it will also help with evaporation and lessen the pool chemical use.

Using a heater is fine but remember the hotter the temperatures, the lesser value the chlorine has because heat eats up pool chlorine very quickly.

Hope this helps and best of luck with your pool


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How Long After Adding Pool Chlorine Is It Safe To Swim..How Soon

by Michelle

How long after adding chlorine to our swimming pool is safe to swim?

Thanks for your question Michelle

It's not about a time question, but when the pool chlorine level is down to 1.5ppm - 3.5ppm.

This depends on the sun and heat which will eat up your pool chlorine even faster.

I always try to error on the side of caution, but for a general rule, about a 2 hour wait is fine.

Some may say 15 - 20 minutes, but I wouldn't want to be the one to swim through a pocket of chlorine with my eyes open.

It's always better to be safe, especially when dealing with adding pool chemicals.

Hope this helps and have a great Summer


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Can I Have Too Many People Swimming

by Eileen
(Riverside, Ca )

We have a home pool 33'x 12'and 6' deep.

In the summer (May through Sept) there are usually 5 people swimminmg daily and 7 to 9 people on the weekends.

Our pool man says that is too many people swiming and it is using more chlorine than it should.

He wants to charge us extra for more chlorine.

I was under the understanding that chlorine was effected mostly by the sun?

Also since we don't swim in the winter (Oct through April) and the sun dosen't shine as much shouldn't that pretty much even out?

Thanks for the question Eileen

Basically, the more people you have in the pool, the more chlorine the pool will use.

This is because of the organic matter that gets into the pool through urine, spit, sweat, make-up, lotions, dead bugs, etc...

Water drag off and evaporation will cause an increase in chlorine as well because you'll be topping off the pool with tap water that contains no chlorine.

The pool is being diluted with fresh water, thus, more chlorine is needed in order to compensate for the new fresh water being added.

All this, and more, will cause the pool to use more chlorine.

It is true that the sun and heat does have a direct impact on chlorine usage.

That's why keeping the stabilizer (CYA) consistent is so important.

Normally, home pools should keep their chlorine level between 1.5 - 3.5ppm and the CYA between 30 - 50ppm.

For a heavily used pool, you'll need to bump up the chlorine a bit because if you keep it too low it may bottom out quickly and the pool will be left without any sanitizer.

The correct number of people swimming in a home pool is subjective and open for opinion.

I believe for lifeguard training and the Red Cross, it says 3sq. feet of water per person.

There are some things you can do to lessen the chlorine usage.

Have your swimmers take a hot soapy shower before entering the pool and take frequent bathroom breaks.

Keep as much water in the pool as possible.

Using a solar cover will help with the evaporation and chemical use.

If you are concerned about the possible increase in chlorine use, you can try to find a pool company that charges a flat monthly fee, chemicals included.

Hope this helps and have a fun and safe swimming season.


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