Newbie Question About FC


Well-known member
Aug 9, 2016
Manorville, NY
Hello everyone so I installed and had my pool last year and did everything with salt and the SWG, however I am about 2 months from opening my pool ow and starting to read up and have my TF-100 test kit now so just trying to understand it.

In order to add FC you just use bleach, excuse my ignorance, but even in SWGs? Last year I would typically go to the pool store have them test it and at the end of it I would dump quite a bit of salt into the deep end to raise get everything right. From what I understand I can just dump liquid bleach into the pool to get the FC levels once I test, even though it is a salt water pool. I know this is probably an extremely stupid question, but have to start somewhere.

Also is the end result so that I am just adding bleach and keeping other things leveled and never really "boosting" my production from the SWG?


Gold Supporter
Jun 8, 2015
Concord, NC
Good morning!

Not stupid at all!! I have a SWG as well and in the colder temps you have to manually add chlorine because the cell doesn't work. I *think* the temp required is around 60° . I keep our pool open year round and so in the winter have had to add plain bleach just a handful of times.

Adding salt to the pool doesn't directly increase the FC level - it gives the salt cell something to work with to make the FC.

I'm sure somebody much more expert will be along shortly to help you, but I just happened to see this and wanted to assure you it was not a stupid question.

Keep up the learning here. It's a terrific source of support and information. Do you know how to use Pool Math? You will need to know your CYA first, and then the chart will tell you what to target for your FC.

Hope this helps until the experts come along. :)


Well-known member
Aug 9, 2016
Manorville, NY
Yes just starting to learn. I close mine or my Labrador would jump into it during the middle of the winter and I'm in no mood to chase after her. Looking forward to understanding this a bit better thank you

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Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
Bedford, TX

Welcome to TFP... A Great resource for all your saltwater pool questions... :snorkle:

Just to make sure we are all on the same page... Your SWCG uses the saltwater to make chlorine. In the summer months you should not have to use bleach unless your SWCG can't keep up with the amount of FC (chlorine) that your pool uses each day.

At the beginning of the season, before you turn the SWCG on for the first time, if you find that you have very little chlorine left in the pool, it is easier on the SWCG to bring the FC level up by using Liquid Chlorine or bleach. After your FC is close to where you want it, then turn your SWCG back on.

You will still have to make sure that the salt level in your pool is correct by testing yourself or going to the pool store. I would not rely on any of their other tests, but they do pretty well on salt testing. Also, your SWCG should report the amount of salt it sees in the pool water.

Using the SWCG's "boost" mode just uses up the total amount of chlorine that a cell can produce in its lifetime. I never use the boost mode for any reason.

Thanks for posting a great question...

Jim R.


LifeTime Supporter
TFP Guide
Jan 18, 2015
Bunbury, WA, Australia
Yep a SWG is like a mini-chlorine making factory. It turns the salt into chlorine through electrolysis. Whether you use a SWG to make chlorine or add it manually through bleach or other chemicals, the end result is the same- chlorine.

The amount of chlorine added by a SWG is relative to the pump run-time and output setting and it good at adding chlorine gradually albeit in smaller amounts. You can add bleach or liquid chlorine to supplement the SWG and many people add a dose here or there, especially when it gets hot and/or you have a heavy bather load.