# Thread: SWG to Bleach Equivalence

1. ## SWG to Bleach Equivalence

Question - does anyone have a good way to calculate the equivalent amount of sodium hypochlorite that an SWG generates?

For example, my IC40 manual says that it is capable if producing 1.4 lbs of "chlorine" per 24 hrs. I'm going to assume that the word "chlorine" means "hypochlorite" as opposed to chlorine gas (could be wrong on that point). So what is that equivalent to in units of say 10% bleach?

Is there a better way to calculate how much FC is put into the water for a given SWG run time and percentage ON (Pentair IC40 uses a duty cycle method where the % setting is just the % ON during a 1hr time period, 50% = 30min ON / 30 min OFF)

2. ## Re: SWG to Bleach Equivalence

That is pounds of chlorine gas. Plug it into the effects of adding chemicals at the bottom of PoolMath.

3. ## Re: SWG to Bleach Equivalence

Originally Posted by jblizzle
That is pounds of chlorine gas. Plug it into the effects of adding chemicals at the bottom of PoolMath.
Ah, ok, so they do mean gas.

I tried that on PoolMath but my concern is that the units are locked to "oz". One pound of Cl is going to be a lot of ounces by the good old ideal gas law :

P V = n R T

So I'll have to scratch a couple of pencils together tomorrow to make the conversion of weight to gas volume.

Unless someone happens to have that value handy?

4. ## Re: SWG to Bleach Equivalence

It's ounces WEIGHT so 1 pound of chlorine gas is 16 ounces -- no gas law required for that conversion.

1.4 pounds chlorine gas is 16*1.4 = 22.4 ounces which putting into PoolMath along with 17,000 gallons gives 9.9 ppm FC. So that is 9.9/24 = 0.41 ppm FC per hour so if run for 8 hours that is 3.3 ppm FC. It should be enough, but it's not oversized by much since you generally don't want to have to run the pump for very long. For a run-time percentage, just multiply this result by that percentage.

5. ## Re: SWG to Bleach Equivalence

Originally Posted by chem geek
It's ounces WEIGHT so 1 pound of chlorine gas is 16 ounces -- no gas law required for that conversion.

1.4 pounds chlorine gas is 16*1.4 = 22.4 ounces which putting into PoolMath along with 17,000 gallons gives 9.9 ppm FC. So that is 9.9/24 = 0.41 ppm FC per hour so if run for 8 hours that is 3.3 ppm FC. It should be enough, but it's not oversized by much since you generally don't want to have to run the pump for very long. For a run-time percentage, just multiply this result by that percentage.
Thanks!!

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