Understanding Bleach Degradation

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Here’s another one that’s good if you can convert from celsius.

Hell… I got curious and did some maths.


  1. 90 degree average temp, bleach will degrade about .16% per day over 30 days. I.e. from about 13% to 8%.

  2. If you can keep it around 70 degrees it may degrade 1.5% over 30 days.

  3. If you have bleach on hand for 30 days you’re not marketing enough. :slight_smile:



Had a discussion some time ago with @CaCO3Girl about this.

Fresh hot 15% SH will degrade to around 6% over 60 ish days (regardless of temp but that higher temps accelerates this process).

If I remember correctly our Resident Chemist stated that chlorine really does not like to be in concentrations above 5% for long which is why all the household bleach is sold at 3-5%. At that point it is very stable for a long time.

@squidskc +1 You should only have the amount of SH on hand that you can use in 30 days. Having agreed with that, when you have limited suppliers if even at 30 days you have 8% lets say, with 20 gal left, you are probably still better off buying 55 gal drum than buying locally at least around here by the gallon. We have crazy stupid prices around here for SH - as much as $6/gal at the pool supply (and at that it is not even fresh - last time I got it from them it was 5 months old - mind you it was Feb with Oct manufacture date stamp).

I find getting 10% from Home Depot is hotter SH than what the pool suppliers give me (at least during winter). Maybe it will be different during summer, but Home Depot runs $3/gal for 10% verses $6/gal for 12.5%. Once diluted, the Home Depot prices nets out a lower cost per diluted 1% Sh mix gallon in the end.

6%…but you were SO close man!

To add to Brodies comments -

It is important that we understand the true cost of chemicals and how to maximize profits. Let’s assume the pool supply has 12.5% and Home Depot is 10%. It is all relative - if the pool supply is really 10% and Home Depot is really 8% then the logic still applies. For those of you in Florida (cough cough @florida_condo_cleani) you can ignore this with your $1/gal 12.5% on every corner.

Since we typically dilute it down, I am going to use a 1% final mix for this analysis.

Home Depot - $3/gal of 10%
Pool Supply - $5/gal of 12.5%

1 gal of 10% plus 10 gal water = 11 total gal of 1% mix at a cost of $.27 per gal
1 gal of 12.5% plus 12 gal water = 13 total gal of 1% mix at a cost of $.38 per gal

In this example it would be advatagous to forgo the pool supply house to get your SH. Let’s say you use 250 gal a month of SH. Using the above data, by going to the pool supply you would be paying about $300 a month more for your final 1% mix. Annually (assuming you work 12 months a year which I know many of you don’t) that is $3600 a year more.

For pricing to be considered even, 12.5% SH would need to have a price point of $3.45 gal to net out even.

For those of you without access to a reliable quality SH provider, going to the local pool supply may not be the best option. Do the math on your prices locally and determine what is the best source for you to maximize your profitability.

The numbers presented are the reality in my neck of the woods. Actually the local pool supply plays games with each employees there selling it at a different price. A complete joke of an operation. Why they can not set-up customer accounts with agreed pricing is crazy, one reason I won’t do business with them.