comments:
Lodingi posted on r/aquariums2w
I know I'm late to the conversation, but I had the same issue, I could never keep invertebrates alive in my well established tank. One day, I was talking to the owner of my local fish store about it, and she asked if I had copper plumbing. When I told her I did, she immediately said that was likely the cause. She recommended a product to remove the copper, so I bought it and added it to my canister filter. After waiting 48 hours, I introduced a couple of ghost shrimp and some snails, and they've been doing great ever since. I was also advised to add a calcium shell to the tank to help keep them healthy, which I've continued to do. Here's the product link