Age of bleach

Now that it’s getting closer to winter my 30 gal bottles of sh have older dates. Just got 2 delivered that are from late August. It is 12.5% but after let’s say 3 months how strong can it be now? I thought I read that after just 1 month it will drop to 10%, so hoping it’s not like 6% now. I always use full strength on my mixes because I have an 8gpm machine and use the 5-8gpm injector for max flow during soap application. I also mostly do stucco so need the higher percentage. Is 3 month old sh garbage?

No idea, never hold to it too long.
If by the time i winterize, i dump what us left.
Or use it for cleaning

I think I’ll be cleaning until 2020. Worse case maybe I’ll just force feed my injector to get a lot on the wall but that’s gonna cost a lot more…

That or make your mix more stout. My injector pull about 1:7 or 1:8 so i can ds staright 6% sh and be ok if needed. I mix the 12.5% 50:50. From whay I’ve read SH stabilizes around 6-7 % so you can make it work

What kind of injector are you running to get that high of a pull? I thought I saw you were at 5.5 gpm, right?

I upgraded to an 8gpm hydrotek scx30008. I use a stainless steel super suds sucker from Envirospec and have a 5.3gpm 12v pump in line to force feed the injector when necessary. The supersuds sucker has 3 different nozzles that can be interchanged. I was using the 3-5 but when I got the 8gpm machine I noticed that the soaping was painfully slow. I swapped out to the 5-8 gpm injector and now barely notice a difference between when the bypass is on or not. If I need roof or flat work mix (4%) I turn the pump on. It really sucks the ds tank down fast! I used to use 5 gal buckets to mix but now have two 55 gal Vertical tanks. One for sh in bulk and the other as my mix tank. On real big jobs, like the reading cinemas we just cleaned, ill load 40-45 gal of sh into the bleach tank and add my green and terra wash 6x into the whole thing. For stucco turn the pump on and wash away for almost 2 full days on one mix. I Plan on doing the same for this concrete tile roof if surface cleaning with the mosmatic roof surface cleaner is not a good option.

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I know nothing, but this link might help you answer your question (page 3)

The variables are too numerous to quantify, light, heat, date, strength, type of container, PH, have any contaminants entered, etc. The only thing that I gather from every scientific piece I have read so far is that it does not stabilize at any point, it would continually degrade. The stronger the initial strength, the faster it degrades. I’m just a dumb hillbilly, not a chemist.

I surmise from the posts that I have read on this site, that the big operators go through it so quickly that shelf life doesn’t mean anything to them, it is gone before it gets old. The medium operators burn through it pretty steadily, so they only face shelf life issues towards the end of their season. Hence, the posts on numerous threads stating that they bump up their mix. Just my .02 and I could be really wrong. I’m still learning, and will use this opportunity for someone to step in and correct my understanding of what I’ve been reading. I currently have at least 7 PDFs saved for SH decomposition from chemical companies, I just need to learn some of the chemistry to understand it better…


Don’t be so hard on yourself man. You clearly have an aptitude for logic and a great deal of common sense. That goes way farther than memorizing some algorithm. Appreciate your input and willingness to help! The sh was stored in an airtight opaque container in a temp controlled warehouse. I found some sh testing kits online ranging from $120 to $64. I may invest in one to more accurately make my mixes. A deep breath of it works too but would like to keep my own reasoning skills lol

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Thanks. I can’t copy and paste from this one PDF I have, but they state that the optimal temperature for storage is 60 degrees Fahrenheit to slow down the degradation/decompostion. Another PDF also gave a rough time frame of 6 months, but did not break it down into the percentages (strength) at each month. They referenced another study, but I haven’t located that one yet. I guess I’m lucky, I have had plenty of free time to read.

Yeah, taking a wiff isn’t the best idea :grin:

I believe it was pointed out the 12% will eventually stabilize at 6%, just not sure the timeline.

From page 3 it said 9.24% after 2 months. I’m good with that! My container was actually tested 9-11 and a good amount being used this week

I’d love to see that data, I’ve been all over the internet looking for info from different chemical companies, and haven’t seen any say that it stabilizes over time. I’m not disputing what you are saying and I would love to see that it does. I have read stuff that gets way too technical for me on how to stabilize it, but they all say to do it in a lab. Where is the fun in that?

I’ve seen a few houses go up in smoke from some amateur “chemists” making recreational chemicals.

You could channel a certain chemist on here, she could help with the stats.

I was told not to bother her in another thread, to do searches, which I have been. To me, a guy who has to know everything, so I can forget it later, there has to be a definitive answer. This article - leads me to believe that the life is 6 months. They even state that clorox bumps it up (sh) because they know it is going to start breaking down during shipping, especially during summer heat. I read a scientific piece where they put the date at 166 days (effective). Most of the studies I have read are being done by people in the medical field, more specifically, dentists. Once again, relating this to pressure washing, if time lessens it’s ability to kill algae/mold/mildew I would want to know that. I would be a small time operator, so storage would be an issue.

40% Sodium Hypochlorite this is what she said in an earlier thread if I linked it right

I have to edit this again, here is the gist of my question: If 6% (more or less) is only effective for 6 months, and higher strength/concentrations break down quicker, at what point does 12.5 or 10% become ineffective for removing algae/mold/mildew. I won’t throw in the variables of higher temperatures, although that is likely to be the case.

Think i’m done wrapping my head around this. Gotta get up early for the vets day parade.

You can bother me, lol! It just may take me awhile to reply. This is a good quick fact sheet that sums up a lot.


That’s pretty cool. I wish it was in American because I have no idea what 25° Celsius is lol

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Here is a Formula to convert any given temperature in Celsius to Fahrenheit (25°C × 9/5) + 32 = 68°F
or °C X 1.8 + 32 will give you temp. in Fahrenheit, if that helps you or anyone else for this sheet or anything else.


That seems like a lot of work. I just go “Okay Google what is 25 degrees Celsius in Fahrenheit?” LOL


Lol. On my one machine it’s got the temp dial, Farenheit and Celsius are both on there. Told my guy to turn it up to 120 degrees to melt some oil off a motor bay that blew a turbo line, couple minutes later I was washing away, Saying, Damn this gun is getting hot to hold ! He turned the dial looking at Celsius, which is 248 American degrees. I only hire the best. :crazy_face: