Matt, If you slow the flow in the second reactor via a valve you would cause back pressure on the first reactor which would slow it to the speed you are achieving in the second. Hope you follow me. Running GFO and carbon there is no need to have different rates. Just pack the carbon tight and it will not tumble. In order for the GFO to tumble for lack of a better word you will be going slow enough anyway for the water to have enough contact time and work.
Taz
PS when I say tumble the GFO what I mean it start the water flow slowly until you see the media lift a little and maybe with a hair more flow you will see only the very top layer move/bubble slightly like it is percolating. You have to watch very closely to see this action.
Taz
PS when I say tumble the GFO what I mean it start the water flow slowly until you see the media lift a little and maybe with a hair more flow you will see only the very top layer move/bubble slightly like it is percolating. You have to watch very closely to see this action.