From what I know you slowly remove the gfo off line
Keep both online, more than likely there'll be residual PO4 to be removed after the NO3 reaches undetectable levels and another export mechanism is required; GFO. Unless you're one of the lucky people that can get NO3/PO4 proportionately reduced.
http://reefkeeping.com/joomla/index...ar-dosing-methodology-for-the-marine-aquarium
Carbon, keep it going.
Keep both online, more than likely there'll be residual PO4 to be removed after the NO3 reaches undetectable levels and another export mechanism is required; GFO. Unless you're one of the lucky people that can get NO3/PO4 proportionately reduced.
http://reefkeeping.com/joomla/index...ar-dosing-methodology-for-the-marine-aquarium
Carbon, keep it going.