I currently am using a 3600 gph pump which sends the water to a wheelbarrow filled with rock and then back to the pond (see photos on my intro post). I plan on using a 2" pipe into the blue barrel and a 3" overflow pipe. My question: what kind of media should I use in the barrel? I have planned on using rock, larger at the bottom and smaller as it gets to the top, but I've been reading that rock is not the best idea. I've also planned on keeping some floating plants in the barrel. Any help, suggestions would be appreciated.