Invertebrate failure in 90

[Steve and his Animals]

I service a 90 gallon fowlr tank that at one point, years ago, had coppersafe in it. Since then, we have replaced the sand and used various absorbers (cuprisorb, polypads, purigen, chemipure) to remove any traces of the copper. Polypads continue to come out brown not blue, etc.

Even so, the tank cannot seem to house any invertebrates: snails are added and most seem to never move from their introductory placements until they die. The only invert that seemed to do decently was a larger banded coral shrimp, which was in the tank for at least 6 months before seeing it listless and slow to react (but still alive) today.

The only fish I was suspect of was the picasso trigger, but the owner seems to swear he never sees it attack anything. Only other fish are a heniochus and (breeding) pair of ocellaris.

The tank desperately needs invertebrates to survive for algae cleanup. Any ideas?

 

[Psyduck]

I dont think you can completely rid of copper once its in the main tank. The rocks will slowly leach forever. You will have to replace everything in the tank.

 

[Steve and his Animals]

I dont think you can completely rid of copper once its in the main tank. The rocks will slowly leach forever. You will have to replace everything in the tank.

I was hoping this to be more of a last resort, but I don't see how using all these copper absorbers and them coming out clean after all this time makes any sense if this is the case.