Ok so I dirted my tank, everything is going great except high nitrates, they're coming under control now, but I added some cambomba in order to suck them up. This came with the normal lead weights round the bottom. I was under the impression that these were shrimp save, being a zinc alloy and oxidised in order to make them inert. Yet my shrimp are dying like there's some metal poisning going down.

I've taken the weights out now and I'm hoping for the best, but I just wondered if anyone had had a simillar fatality rate with shrimps, and what cause was? Has anyone else had issues with lead plant weights and Amano Shrimp at all? Just trying to rule out the potential causes......

Thanks all  :(