Granular Ferric Oxide (GFO) Instructions

We have three different types of GFO: Granular, Pelletized and High Capacity Granular. They have the following differences:

• Granular GFO is generally what most people are familiar with.  Granular GFO works well in reactors that slowly tumble the material.
• Pelletized GFO is slightly larger than the granular form and has a few slight advantages. The pellets are harder, have a more uniform shape/size and lose less material into the water. They also contain slightly more phosphate removing material for the same volume of material. Pellets work well in reactors but can also be used in a simple filter bag.
• High Capacity Granular (HC GFO) is our premium GFO and comes with several distinct advantages over the other GFO's. HC GFO is able to remove roughly twice as much phosphate for the same volume of material. This means it will last longer and require less maintenance. The particles are extremely hard and even better then the Pelletized GFO at reducing the effects of water abrasion. HC GFO works very well in both a reactor and filter bag. If you are going to be using a filter bag with your GFO this is the preferred product.   

Using GFO in a Phosphate Reactor

1. Determine the amount of GFO needed. Start with 2 grams of Granular or Pelletized GFO (1 gram of HC GFO) per gallon of water in the system. After a few months the organisms in the tank will have adjusted to the lower phosphate environment. At this time the amount of Granular and Pelletized GFO can be increased to 3-5 grams (2-3 grams of HC GFO) per gallon of water. Please note that these amounts are suggested starting points. As each tank is different, it may be necessary to vary the amount used for better results.
2. Rinse the GFO. Place the GFO in the reactor and return to the tank. Remove the return line on the reactor from the sump or tank and place in a waste bucket. Turn on the reactor to rinse the material. Once the water runs clear place the return line back in the tank.
3. Adjust the flow rate. Once the GFO is rinsed adjust the water flow by turning the ball valve on the reactor. There should be just enough flow so the GFO gently tumbles. This will prohibit the GFO from forming one big chunk. If the media is tumbling to vigorously the particles will grind against each other and create small fines that will be released back into the tank.

Using the GFO in a Media Bag

1. Determine the amount of GFO needed. Start with 2 grams of Granular or Pelletized GFO (1 gram of HC GFO) per gallon of water in the system. After a few months the organisms in the tank will have adjusted to the lower phosphate environment. At this time the amount of Granular and Pelletized GFO can be increased to 3-5 grams (2-3 grams of HC GFO) per gallon of water. Please note that these amounts are suggested starting points. As each tank is different it may be necessary to vary the amount used for better results.
2. Rinse the GFO. Rinse with RO/DI water or water from the tank to remove the dust created from storage and transport. Avoid grinding the material back and forth as this will cause more dust. Simple let the water run over the mesh bag or gently swish the bag through the water.
3. Place the bag in an area of the tank with good flow, such as the sump.

***If you use a filter bag for your GFO we suggest mixing with activated carbon. This will prevent the GFO from solidifying***