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Water quality/expiration date
For my
homecrafting, creams, toners, etc., I use 5 liter jerrycans water that’s been
distilled and deionized in accordance with some German quality standards (see picture
below).
I also use this water to rinse i.a. measuring cylinders, the probe of the pH
meter and prepare buffer fluids for the pH meter. Even with all that I could do
(in theory) for several months with only 1 jerrycan. I throw the rest away
after 1 or 2 weeks because it doesn’t feel right to use any longer. (At work we
throw the water we use for non sterile dermatics away after 1 day, so it feels almost
awkward to use it so much longer in private!).I can get 1 liter bottles from DIY stores, but those are in comparison insanely
expensive (around 5 dollars for 1 liter of distilled water).Another option is use 1 liter bottles of water of a lower water quality (‘demineralized’
water) from the supermarkets/drugstores (you can’t get distilled/deionized
water in supermarkets/drugstores here).- My
question is: is it, from a microbial point of view, safe to use the lower
quality ‘demineralized’ water? Depending on the formula, I can’t always use
sequestering agents. - And
what would be a safe expiration date for these types of water quality?
(The preservatives I use the most are Phenonip
P4 (1%), Germall Liquid Plus (0,5%) and Germaben II (1%). If I use a blend of phenoxyethanol +
ethylhexylglycerin (90/10), I follow the hurdle approach (usually I combine it with
0.1-0.2% disodium EDTA, other Aw reducers like caprylyl glycol, glyceryl
caprylate). - My
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