Just to be clear, most reputable GFO "packagers" suggests not to tumble the media. They do suggest to allow the top few granules to "tumble" at the surface. This means the majority (99.9%) of the GFO is not tumbling.
Here's from PhosBan's instructions:
4. Initial Operation and Adjustment Once the lid is securely fastened, the reactor is level, all of the hoses are securely attached, and the pump is located in the aquarium or sump, direct the return hose into a bucket, open the ball valve, and connect the pump to the mains electricity. Allow water to fill the reactor for 2 to 3 seconds and then close the ball valve to stop the flow. Partially open the valve slowly to about 20 gph to purge air from the outflow pipe and allow the initial dusty 1/2 gallon of water to empty into the bucket. When the water runs clear, close the valve and reposition the return hose to feed water back to the aquarium. Adjust the flow with the ball valve so that the PhosBan granules are tumbling slightly at the surface. A section of clear water will be located above the granules.
And from BRS:
For use in a media reactor:
1. Place GFO in suitable reactor
2. Place the reactor's return line into a bucket or sink
3. Turn on the feed pump to flush the fines from the GFO until the water runs clear
4. Place the return line in the tank
5. Reduce the flow through the reactor so the GFO barely tumbles on the surface.
6. Do not allow the material to vigorously tumble.
7. Change the media when phosphate levels rise, typically 4-8 weeks.
There are a bunch of companies that package GFO with horrible directions. Some suggest dosages 20x typical that would surely stress corals. Others recommend fluidizing the GFO like you would biopellets. Many reefers fluidize GFO to prevent clumping of the GFO in the reactor but this is not necessary. There are many methods to prevent clumping without fluidizing the media.
Here's from PhosBan's instructions:
4. Initial Operation and Adjustment Once the lid is securely fastened, the reactor is level, all of the hoses are securely attached, and the pump is located in the aquarium or sump, direct the return hose into a bucket, open the ball valve, and connect the pump to the mains electricity. Allow water to fill the reactor for 2 to 3 seconds and then close the ball valve to stop the flow. Partially open the valve slowly to about 20 gph to purge air from the outflow pipe and allow the initial dusty 1/2 gallon of water to empty into the bucket. When the water runs clear, close the valve and reposition the return hose to feed water back to the aquarium. Adjust the flow with the ball valve so that the PhosBan granules are tumbling slightly at the surface. A section of clear water will be located above the granules.
And from BRS:
For use in a media reactor:
1. Place GFO in suitable reactor
2. Place the reactor's return line into a bucket or sink
3. Turn on the feed pump to flush the fines from the GFO until the water runs clear
4. Place the return line in the tank
5. Reduce the flow through the reactor so the GFO barely tumbles on the surface.
6. Do not allow the material to vigorously tumble.
7. Change the media when phosphate levels rise, typically 4-8 weeks.
There are a bunch of companies that package GFO with horrible directions. Some suggest dosages 20x typical that would surely stress corals. Others recommend fluidizing the GFO like you would biopellets. Many reefers fluidize GFO to prevent clumping of the GFO in the reactor but this is not necessary. There are many methods to prevent clumping without fluidizing the media.
