Today's Dumb Question - Best Process for adding liquid chlorine?


Active member
Jun 29, 2017
Augusta Township, Michigan
Hello all,

Now that my pool is sparkling clean, I want to make sure it stays that way. Due to high CYA, I'm not going to use the chlorine tablets but instead add liquid to maintain my level. My question is, what is the best way for doing that? I read through all of the stuff on Pool School but didn't really find what I was looking for.

According to the CYA/chlorine chart, I want to maintain my FC at 8-10 PPM. Does that mean I add chlorine when it gets down to 8 ppm, and only add enough to go back to 10 ppm? Or do I let it get lower than 8 before adding? Do I add enough to get it up to, say, 12 ppm so that when it goes to work I still have around 8-10 in the pool?

I assume I'm going to have to add some amount of chlorine each day, and I want to add it when the pump is on. Correct? I currently have my pump set to run from 11 am - 7 PM every day, so 11 would be the time I would add, is that okay?

Bama Rambler

Mod Squad
TFP Expert
Bronze Supporter
LifeTime Supporter
Jun 22, 2009
SouthWest Alabama
Each person has their own 'best way', mine is using a peristaltic pump on a timer that'd set to run the needed time to dose the needed amount of bleach.

My timer is actually a remote controlled outdoor outlet controlled by my home automation system, but it can be as simple as a standalone timer.

Once you know how much FC your pool loses each day you can adjust the base FC (8ppm) and then test and add enough bleach to add that many ppm FC to your pool and you should be good until the next time you add bleach. (For instance, your pool normally loses 3ppm per day and your pool is 12,000 gallons. That means that you normally need to add 46oz of 10% bleach every day.

Divin Dave

TFP Expert
LifeTime Supporter
Oct 2, 2013
Longview, Texas
Hi Franz
For example if your recommended FC level is 8-10, then you dont want your FC to ever fall below 8 if you can help it.
Its OK to go a little above 10, but a lot above 10 is a waste of chlorine, because it wont provide any real benefit. So just shoot for 10 or 11.

As for your pump running when you add chlorine, yes. You can add chlorine at any time the pump is running. Whatever time of day you add it is up to providing that your FC is not below 8. The pump needs to continue to run for 20 or 30 minutes after the chlorine is poured in, so it can get mixed up well in the pool.

hope this helps,


TFP Expert
LifeTime Supporter
Jan 6, 2010
San Dimas, CA (LA County)
Please clarify. You see 8-10 as target? That implies CYA of 70.

In that case, minimum FC is 5, with a target of 8-10. You need to determine your target by testing and dosing. You want to raise FC enough so that it doesn't drop below 5 before you next test and dose. So if you find you that when you target 8 that it has dipped to 4 the next day, you better target 9. Just keep it above the minimum.

When to test is anytime the pump has been on at least half an hour. When to dose is anytime the pump will be on for at least another half hour. Beyond that it';s wide open. Just try to be consistent so the FC never dips velow minimum.