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Where are the references? What concentration bleach? From TFA: "Unfortunately, bleach solutions need to be made fresh every day" From CDC[0]: "If chlorine sol
by mhb 7y ago
Where are the references? What concentration bleach?
From TFA: "Unfortunately, bleach solutions need to be made fresh every day"
From CDC[0]: "If chlorine solution is not prepared fresh daily, it can be stored at room temperature for up to 30 days in a capped, opaque plastic bottle with a 50% reduction in chlorine concentration after 30 days of storage (e.g., 1000 ppm chlorine [approximately a 1:50 dilution] at day 0 decreases to 500 ppm chlorine by day 30)."
[0] https://www.cdc.gov/infectioncontrol/guidelines/disinfection/index.htmlhttps://www.cdc.gov/infectioncontrol/guidelines/disinfection/index.html https://www.cdc.gov/infectioncontrol/guidelines/disinfection...
- amluto 7y agoAs I understand it, chlorine loss is not a first order process like this. The more concentrated the solution, the shorter the half life. It may well be that there is a first order effect as well, and the 30 day half-life is a conservative estimate when diluted with worst-case impurities in tap water.
- mhb 7y agoI'm curious how this applies to the bleach sold in stores. Are they doing something to make that last longer? Otherwise it sounds like they should be treating it with perishability similar to milk.
- amluto 7y agoIt’s not that bad. Look at the bottom of this page: https://www.odysseymanufacturing.com/ultrachlor-bleach https://www.odysseymanufacturing.com/ultrachlor-bleach A few things here are worth noting. Highly pure bleach is more stable. And chlorate is undesirable and mildly toxic. You don’t want too much in your drinking water. From experience, one should only buy bleach from stores with decent turnover. Bleach from the corner store may well be dead.
- adanto6840 7y agoGood questions and I'm curious on the actual science too. We're using liquid pool chlorine diluted with water -- pool chlorine is just higher-concentration bleach. Although not scientific by any stretch, I know that the general guidance (and my experience from chlorinating & testing pools) is that you want to check the dates on the chlorine when purchasing because the strength can be substantially lower than stated if it's been sitting on the shelf for a long time. My understanding is that the effect is worse if the product has been sitting outside in direct sunlight / high heat (ie outdoors at a home improvement store), which I believe causes concentration to drop faster. If you're having trouble finding bleach though, likely can get some at a pool store or a big-box home improvement store in the pool chemicals area. We just mix it down to suitably diluted concentrations in a spray bottle -- readily available & much cheaper than off-the-shelf spray products. I wasn't aware it might be 50% lower concentration in 30-days though, will have to re-mix ours here soon. But that's still small potatoes overall, a gallon of bleach goes a long way and has lots of uses. :)