Bleach solution (soaking pots for re-use)

[Fairorchids]

Regular bleach is sold in a 5.25% concentration. In the past I have heard people say to use a 5% bleach solution, but I do not know anyone using full strength bleach to soak old pots.

In an old thread I found one recomendation, to use 1 part bleach to only 1.1/2 to 2.1/2 parts water.

Diluting the bleach with:

19 parts water = 0.25% bleach in solution
9 parts water = 0.5% bleach in solution
1.5 parts water = 2.0% bleach in solution

Does anyone know of a rigorous study of this question?

I would cosider using close to full strength bleach, if I could re-use the bleach, but bleach 'evaporates' out of the water if left standing in an open container (reportedly at 0.75 g/day). 1 gallon contains about 295 g of sodiumhypochlorite, so it should be about inert after 13 months (and obviously be progressively less effective over this time line).

I guess pouring it back in the jug would eliminate the evaporation, but it is a lot of handling of a fairly nasty liquid.