Yes I have been using them for about 6 months now with mixed results. I am using a Reef Octopus with about 1 liter of pellets in it on my 200 gallon of water volume system.
At first I started to see the positive effects in the first month or so. Building up the volume as directed, adding about 1 cup of pellets every 7-14 days. Taking it slow.
I went from .50 ppm Phosphate down to about .25. Then things kind of planed out. I kept adding pellets to see if I could get lower but never got passed the .25 ppm bar.
I am not sure what I need to do next to get them going like they should be. I think I have them tumbling right as all of the pellets are moving at a constant rate. In fact I have recently started to turn the flow down some to see if that will help or not. My thought was that maybe by tumbling to fast I was "Scrubbing" off the bacteria? Just a guess really.
As far as BRS, I am a HUGE fan of all their products as they have never let me down. SO I am still under the assumption that I am doing something wrong in my set up and that I am not maximizing the effect.