SWG vs Bleach

[JoyfulNoise]

All of this input is great, thanks. Back to one of my original questions: 1 jug of bleach = how many pounds of chlorine? Most of the specs on the generators have pounds/day and I wanted to know how many jugs that would be in comparison.

The calculation is not hard to do, but it rests on some assumption. If you want to know the weight percentage of available chlorine in a bottle of bleach, then you take the weight percent of sodium hypochlorite and multiply that by the ratio of the molar masses of chlorine gas (Cl2) to sodium hypochlorite (NaOCl), or

Weight % Available Chlorine = Weight % NaOCl * (Cl2 g/mole) / (NaOCl g/mole)

Where,

NaOCl g/mole = 74.442
Cl2 g/mole = 70.906

For example, a 121oz bottle of 8.25% Clorox has,

8.25% * (70.906 / 74.442) = 7.86 wt% available Cl2

One minor issue when trying to calculate the actual weight of Cl2 is that the specific gravity of bleach (density or lbs/gal) can vary depending on the manufacturer. Bleach has excess lye in it to raise its pH above 11 so that the hypochlorite remains stable in solution. So solution weights will vary a little.

As others have mentioned, and as I posted in my first response, it's just easier to calculate the FC using PoolMath and compare. In your pool volume, 1 gal of 8.25% bleach adds 3.3ppm FC. The IC-40 running at 100% and 24 hours adds 6.9ppm FC. So running the IC-40 for 12 hours per day will be a close approximation of 1 gal of 8.25% bleach. This is why I suggested you might be better if with an IC-60.

Best wishes,
Matt


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006

 

[Pool Tool]

Griswald - Yes, a consistent level is "better" or at least less likely to cause issues. That is why the target FC levels for a SWG pool are considerably lower than a standard pool as it assumed an SWG pool FC is consistent while a standard pool is going to have the large FC swings as you noted.

 

[needsajet]

1 jug of bleach = how many pounds of chlorine?

If the jug is one US gallon and the concentration is 8.25%, it's about 0.8 lb.

 

[otter86753]

We tend to also have a high chlorine demand because of not putting our cover on (it's a pain in the butt) and being in direct sun most of the day. Hopefully raising the CYA this year will help even if we don't get a SWG this season. I'm just worried that we'll get a generator and it won't be able to keep up with the demand and I'll still have to add bleach all of the time. Probably not as much but the whole thought is not having to deal with that, except for SLAM and the occasional big pool party.

I am much further south than you and don't have a cover for my pool at all and my SWG keeps up beautifully in totally blazing full sun all day on the pool. I even have an additional bather load from having my dog swim for therapy 2-3 times a week which is equivalent of 5-10 person bather load. Once the water is balanced and more importantly algae free, if you have the correct size cell, it should be just fine to maintain your FC level. There are RARE instances where before a large party, I will add some bleach, but that is maybe twice a season.