Loosing fish dont know why

[fishytime]

I am thinking that perhaps the fact that you have put a large bio-load in what is basically a brand new set up may be your issue. What brand and how old are your test kits? Have you taken a sample of your water to your LFS to confirm your readings? If your problem started more than a month ago that would mean your tank was only two months ish old, which is fairly new to be adding that many fish at once. It is possible that your fish are dying from water quality and your clean up crew are taking care of the carcass.