wrote in message
oups.com...
| Maybe someone can help me. I have a 90 gallon tank set up with
live

I would be tempted to agree with Pszemol as long as the corpses are
consistant with traumatic death. Mantis shrimp are monsters. If not,
I would head in another direction. Have you found corpses at all? If
they appear unmolested, water is likely the issue. As John said,
provide us or your trusted LFS with the specific water parameters.
"Levels check out ok" just isn't enough, as you may be relying on
false information. Do a full battery of tests and check it out. A,
N&N, of course, then phosphates, alk, everything you have kits for.
As an aside, check for metal of ANY kind in contact with your
water. Metal heaters, return and powerhead pump impeller shafts...I
had a problem much like yours and it turned out to be rusting metal
from something I'd rather not discuss because of how bone stick stone
stupid of me it was to have had it in there...but I digress.....