I use either the zippered small lingerie bags for washing machines or regular media bags to hold the Seachem Matrix though I bought the Pond Matrix because it is much larger.
I recommend bagging the media sooner rather than later to avoid the chance that any small pieces would damage the impeller especially if you bought the smaller size Matrix. I know it's a pain to open the filter up again but you'll be kicking yourself if you need to replace the pump motor or if a piece of media jams the impeller and the filter turns off.
I recommend bagging the media sooner rather than later to avoid the chance that any small pieces would damage the impeller especially if you bought the smaller size Matrix. I know it's a pain to open the filter up again but you'll be kicking yourself if you need to replace the pump motor or if a piece of media jams the impeller and the filter turns off.