Copper

[peteg]

HI,

I have tested my water for copper and it seems there is some present in my tank but ive looked for ages to try and find what levels become very bad for snails and shrimps. I know ideally no copper is best, having read what feels like the whole internet, it seems that most can cope with small/trace amounts but nowhere seems to give figures.

So does anyone know any figures of ok/bad/verybad/death copper concerntrations?
Does anyone have snails/shrimp and have copper readings?

Thank you.