Hello; Yes this is what I was driving at in my convoluted way. The SAFE being a reducer might be reducing the O2 as RD mentioned for a while. Maybe not enough to kill off the bb but enough to shut them down a bit.overdose and high bio load I think it is possible that the amount of dissolved oxygen was reduced to a level that it inhibited the the aerobic nitrifying bacteria.
Hello; Yes to this. Maybe not a solution if your dream fish don't do well but the fish that thrive don't die as much.stopped keeping the species that had problems with my tap water.