Difference between revisions of "Breakdown of Bleach Over Time by Storage Temp" - Further Reading

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=What is the loss of strength of stored liquid chlorine over time based on the storage temperature?=  
 
=What is the loss of strength of stored liquid chlorine over time based on the storage temperature?=  
  
<ref>https://www.troublefreepool.com/threads/breakdown-of-bleach-over-time-by-storage-temperature.60837/#post-511942</ref>I finally got around to making a spreadsheet using the rate constants from [https://www.powellfab.com/technical_information/files/810.pdf this link] (same as [http://www.omegachem.com.au/docs/mega_handbook.pdf this link]) plus some fitting and fudge factors to be consistent with half-life and this paper<ref>https://www.odysseymanufacturing.com/ultrachlor-bleach Odyssey Manufacturing</ref>  so I'm showing decomposition rates for 12.5% (trade %) chlorinating liquid below over time vs. temperature.<ref>https://www.troublefreepool.com/threads/breakdown-of-bleach-over-time-by-storage-temperature.60837/page-2#post-725315</ref>
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<ref>https://www.troublefreepool.com/threads/breakdown-of-bleach-over-time-by-storage-temperature.60837/#post-511942</ref>I finally got around to making a spreadsheet using the rate constants from [https://www.powellfab.com/technical_information/files/810.pdf this link] plus some fitting and fudge factors to be consistent with half-life and this paper<ref>https://www.odysseymanufacturing.com/ultrachlor-bleach Odyssey Manufacturing</ref>  so I'm showing decomposition rates for 12.5% (trade %) chlorinating liquid below over time vs. temperature.<ref>https://www.troublefreepool.com/threads/breakdown-of-bleach-over-time-by-storage-temperature.60837/page-2#post-725315</ref>
  
 
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Latest revision as of 18:44, 9 February 2020

What is the loss of strength of stored liquid chlorine over time based on the storage temperature?

[1]I finally got around to making a spreadsheet using the rate constants from this link plus some fitting and fudge factors to be consistent with half-life and this paper[2] so I'm showing decomposition rates for 12.5% (trade %) chlorinating liquid below over time vs. temperature.[3]

Degradation of 12.5% Chlorinating Liquid
TIME 100ºF 95ºF 90ºF 85ºF 80ºF 75ºF 70ºF
Initial 12.50% 12.50% 12.50% 12.50% 12.50% 12.50% 12.50%
1 day 11.92% 12.10% 12.22% 12.31% 12.37% 12.41% 12.44%
2 days 11.42% 11.74% 11.97% 12.13% 12.25% 12.33% 12.39%
3 days 10.99% 11.41% 11.73% 11.96% 12.13% 12.25% 12.33%
4 days 10.61% 11.12% 11.51% 11.80% 12.02% 12.17% 12.28%
5 days 10.28% 10.85% 11.30% 11.65% 11.91% 12.09% 12.22%
6 days 9.98% 10.60% 11.10% 11.50% 11.80% 12.02% 12.17%
1 week 9.71% 10.37% 10.92% 11.36% 11.69% 11.94% 12.12%
2 weeks 8.33% 9.13% 9.87% 10.51% 11.04% 11.46% 11.78%
3 weeks 7.45% 8.29% 9.10% 9.85% 10.50% 11.04% 11.47%
1 month 6.68% 7.51% 8.36% 9.18% 9.93% 10.57% 11.11%
2 months 5.14% 5.90% 6.73% 7.60% 8.49% 9.33% 10.10%
3 months 4.27% 4.95% 5.72% 6.57% 7.48% 8.40% 9.28%
4 months 3.79% 4.42% 5.13% 5.93% 6.81% 7.74% 8.67%
5 months 3.47% 4.05% 4.72% 5.48% 6.33% 7.24% 8.18%
6 months 3.23% 3.78% 4.41% 5.13% 5.95% 6.84% 7.78%


The following shows the decomposition rates for 8.25% (weight % sodium hypochlorite) bleach below over time vs. temperature.

Degradation of 8.25% Bleach
TIME 100ºF 95ºF 90ºF 85ºF 80ºF 75ºF 70ºF
Initial 8.25% 8.25% 8.25% 8.25% 8.25% 8.25% 8.25%
1 day 8.10% 8.15% 8.18% 8.20% 8.22% 8.23% 8.24%
2 days 7.96% 8.05% 8.11% 8.15% 8.19% 8.21% 8.22%
3 days 7.83% 7.95% 8.04% 8.11% 8.15% 8.18% 8.21%
4 days 7.70% 7.86% 7.98% 8.06% 8.12% 8.16% 8.19%
5 days 7.58% 7.77% 7.91% 8.02% 8.09% 8.14% 8.18%
6 days 7.47% 7.69% 7.85% 7.97% 8.06% 8.12% 8.16%
1 week 7.36% 7.61% 7.79% 7.93% 8.03% 8.10% 8.15%
2 weeks 6.75 7.11% 7.42% 7.65% 7.83% 7.96% 8.05%
3 weeks 6.28% 6.72% 7.10% 7.41% 7.65% 7.83% 7.96%
1 month 5.82% 6.31% 6.75% 7.13% 7.43% 7.67% 7.85%
2 months 4.77% 5.32% 5.86% 6.37% 6.82% 7.20% 7.50%
3 months 4.10% 4.64% 5.22% 5.78% 6.32% 6.79% 7.19%
4 months 3.70% 4.22% 4.79% 5.37% 5.94% 6.46% 6.92%
5 months 3.41% 3.92% 4.46% 5.04% 5.63% 6.19% 6.69%
6 months 3.20% 3.68% 4.21% 4.78% 5.37% 5.95% 6.48%

Since day and night temperatures are not the same, one must use a special average that accounts for the non-linearity of degradation as a function of temperature. As derived in this post, the following table shows how you can take a known temperature difference between day and night and add an effective temperature adder to the nighttime temperature to get the effective temperature to look up in the above tables.

TempDiff EffAvgTempAdder
5 2.7
10 5.8
15 9.4
20 13.2
25 17.3
30 21.7
35 26.2
40 30.9


In the Handbook of Chlorination by Geo. C. White, 1999 it states that sodium hypochlorite degradation is as follows:[4]

Temp 77 degrees
Days 12% 10%
10 11.5 9.7
20 11.0 9.0
30 9.7 8.7
40 8.8 8.5
60 6.2 8.0
90 4.7 7.2

Looks like the 10% is more stable for longer periods of time at 77 degrees.

What is the freezing point of Bleach?

Household bleach is commonly sold with 6% chlorine will freeze at roughly 19° Fahrenheit. For 12% Liquid Chlorine commonly sold at Pool Stores the freezing tempature will be roughly 27° Fahrenheit.[5]

How To Test the Actual Chlorine %?

Taylor sells the K-1579 test kit for measuring bleach concentrations in % value. It's marketed to the industrial cleaning industry to be used to test the effectiveness of bleach stored in large volume tanks. A pool owner could use it just as easily but being something one would use very infrequently, it may not be worth the cost.