store bought decor like for fresh water ? that kind of decor isn't really pouris enough to hold bb . you would be better off with live rock , saltwater tanks benefit with live rock in several ways .
1.) it holds the bb that keeps your tank healthy .
2.) provides hiding places for your fish .
3.) live rock acts like a natural filtration
will colonize in the rock .
a list of your parameters would also help I'm thinking they past from ammonia poisoning .
a more detailed description of your tank will help .
along with a picture