How to figure CL from my SWG.

algae builder

Jul 15, 2020
How long would my SWG run to maintain 5 ppm. Just looking for a starting point. I think it will run 12 hrs. max.
i just finished slam. Still using liquid chlorine. Working on getting my high PH, Ta,and Ch down. I was getting a lot of scaleing on the SWG.


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Using PoolMath "Effects of Adding" with 7 grams/hour= 0.37 lbs of chlorine a day I get 3.3 ppm if run at 100% for 12 hours.

An average pool loses about 2-4 ppm of chlorine during the day that the SWG needs to replace.

Brett S

Well-known member
Mar 15, 2019
You can use pool math to figure out how much chlorine your SWG will generate. In your case, with the SWG info and pool size from your signature your system will generate .3ppm of chlorine for each hour it runs. So if it runs for 10 hours it will generate 3ppm of chlorine.

The question of how long to run it to maintain a certain chlorine level is a bit more complicated though, because maintaining a chlorine level means making up for the chlorine that is lost due to the sun and the bathing load and that can vary from one pool to another. It’s not uncommon for a pool to lose 3 to 4ppm of chlorine a day, so that would be running your SWG for 10-13 hours, however, if your pool gets a lot of use and/or a lot of direct sunlight you may need even more than that.

Unfortunately, your SWG may be a bit undersized for your pool. Typically we recommend getting a SWG that‘s rated for twice the capacity of your pool. So with a 6700G pool that would be a SWG that’s rated for at least 13400 gallons.

I would try to run it for the 12 hour max and keep a very close eye on your chlorine levels. If the SWG can’t keep up and your chlorine levels are falling you may need a bigger SWG or you may need to supplement with some liquid chlorine.
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