I currently have a 125 gallon with a 45 gallon sump and was thinking of changing the sump into a fluidized bed. Does anyone have any experience with this? I don't want to remove any portions. Part of the sump is a refugium that I want to keep. The part that would be fluidized is approximately 10-15 gallons. Is this big enough? Do I need to add air or will the waterfall effect of the water flow be enough?