I recently installed a BRS GFO reactor in my sump since my phosphates were beginning to rise, but I can't seem to get my GFO to tumble. I understand that it needs to slowly stumble so it can avoid clumping together. But it should still work even if it is clumped together to remove phosphate albeit with much lower efficiency, right? Or should I pack GFO with phosgaurd and carbon if I can't get it to tumble?