When I enter 8% chlorine into the FC table the calculator it reads "Weight", however when I enter 12.5% the word changes to "Trade". Just wondering what the difference is and why that difference is noted?
Rolo
Rolo
Pool math chlorine question
- Thread starter Rolodetective
- Start date
- May 23, 2015
- 24,446
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Bleach sold for laundry use is sold by weight percent of sodium hypochlorite. That's 6% and 8.25%.
Liquid chlorine sold for pools is typically listed as Trade % which is really a volume %. That covers 10%, 12.5% & 15%.
The difference between weight and volume percent have to do with the specific gravity of the solution. It changes the FC calculations slightly.
Liquid chlorine sold for pools is typically listed as Trade % which is really a volume %. That covers 10%, 12.5% & 15%.
The difference between weight and volume percent have to do with the specific gravity of the solution. It changes the FC calculations slightly.
That is very helpful, JoyfulNoise. Thank you. I didn't realize that the laundry version was listed as weight %.
I just got a quote from a chemical supplier for 12.5% Sodium Hypochlorite. 12.5% by weight is 15% by volume.
I just got a quote from a chemical supplier for 12.5% Sodium Hypochlorite. 12.5% by weight is 15% by volume.
Interesting. So the 8.3% great value bleach at walmart is actually probably a higher percentage of sodium hypochlorite than the 10% liquid chlorine they were selling in the pool section for a while. That would explain why when I switched from the liquid chlorine stuff to the laundry aisle stuff, I didn't have to alter the timing on my stenner to meet my target FC level, even though going from 10% to 8.3% made me think I should have had to use more.
1.45 oz 8.25% provides the same amount of chlorine as 1.16 oz of 10% or 1 oz of 12.5%.
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