I'm a little confused.....
Do you mean they put the mixed solution in a container inside another container ? If so, I'm not sure why or what would be in the other container (oh sorry you said water - still don't know why - unless their container is REALLY big and they are just trying to size it down..).
I believe most people mix the solution right in the crock pot or jar (or whatever container you are using). I sometimes use a plastic container (vented) down in the crock pot in order to place granules or other items I don't want to try to fish out of the pickle. Ya know?
Also, be sure your container is not steel.....it needs to be ceramic, plastic, copper, glass.....(but be careful with glass as far as breakage, heating - not that you want to get pickle to boiling or anything...)
Hope that helps. :)