When you say 'add all', what does that mean? A few tablespoons, a couple of inches, or the entire package? I'd put in about 1" in your media reactor, and keep the flow going through it slow. 90gph is the maximum recommended rate, but you may decide half of that is plenty. The media should rumble slightly, like a moon quake. The output should be crystal clear with no 'fines' exiting the reactor. Those metal fines can sting and bother corals, so it is best to run the reactor into a bucket at first until the water comes out clear, then run it in your sump far away from the return pump. Some people even have the output (effluent) pour into a sock or filter floss to trap those fines. When you have it set up correctly, the output should be measure 0 phosphate. When the effluent measures any PO4, slow down the rate until it measures 0 again. When you can't get 0 out of it any longer, it is time to change the media.