Interesting... I am not sure that anybody has actually tested the electrolyte solution to find out just how much Cr(VI) is in solution. I suspect that the longer you use a cell the more you leach out. So, if you are still using the same electrolyte from 6 months ago, that would be worse than if you just put new electrolyte in yesterday. As to why you are tasting it??? Sounds like you are using reasonable precautions when handling the electrolyte, so I don't know.
Have you started taking any new medications lately? I know that I was once on a pill that left a metallic taste in my mouth.
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Some days I get the sinking feeling that Orwell was an optimist!