Granular Ferric Oxide (GFO) should be used as a part of your tank filtration tools primarily to control phosphate levels. Excess phosphate is one of the main contributors to algae growth, which can quickly become a major problem in a marine system. Controlling your phosphates helps stem current algae issues and prevents future algae outbreaks.
This high-performance filter media is made with a premium iron oxide adsorber designed to target and remove contaminants at the molecular level, bringing professional-grade filtration to your aquarium system.
With a crystalline α-Ferric oxide hydroxide structure and an exceptionally high surface area, it effectively binds and removes phosphates, helping to prevent unwanted algae blooms and maintain ideal nutrient balance.
🧲 Benefits of Using GFO
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Removes phosphate (PO₄³⁻)
GFO chemically binds with phosphate in the water, effectively removing it from the system and locking it away.
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Helps control nuisance algae
Algae like hair algae, bryopsis, or cyanobacteria thrive on phosphate. Lower phosphate = less algae.
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Supports coral health
High phosphates can inhibit calcification in stony corals (SPS/LPS), making it harder for them to build their skeletons. Keeping phosphate low improves coral growth and coloration.
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Reduces Tank Maintenance time
Reducing phosphates in your tank helps control algae, thereby reducing the time spent cleaning your tank glass.
STARTING INSTRUCTIONS
Measure out the amount to be used in your tank. The recommended starting amount is around 1 TBSP per every 4 gallons in tank volume. Follow instructions below based on your method:
FILTER BAG
Add GFO to your filter bag. Rinse the bag with water from your tank or RO/DI water about 30 seconds, or until the water runs clear. Place the bag into your sump or a high flow area of your tank to ensure water is being filtered well through the GFO. Regularly test your tank phosphate levels to ensure GFO is replaced when phosphate levels start rising.
MEDIA REACTOR
Add the measured GFO to your media reactor. Fill a large bucket with fresh or RO/DI water and place your media reactor’s feed pump in the bucket, and the reactor outlet in a sink. Pump water through the reactor for about 30 seconds, or until the water runs clear. Water entry speed should gently tumble the GFO to avoid pulverizing the media. Carefully dispose of any water remaining inside the reactor before installing.
MAINTENANCE INSTRUCTIONS:
Phosphate levels may increase rapidly during first time use. Monitor with a test kit during the first week used. Replace GFO once phosphates begin to rise after initial use. GFO can be replaced every 4-8 weeks after the initial change, or as needed if phosphate levels begin to increase.
Catalytic Activated Carbon
is a highly effective and rapid method to remove harmful dissolved organic compounds (DOCs) and toxins like chlorine, chloramines, and hydrogen sulfide from aquarium water. This carbon also clears out yellow tints in your water, eliminates odors, removes toxins and reduces algae growth. Regular use greatly improves water clarity and light penetration in your tank, allowing your corals to receive more light and improve growth and appearance.
This virgin activated carbon comes in a granular form, made from selected grades of coconut shells. Originally produced for water purification, this type of carbon can also be used in RO/DI filtration systems.
STARTING INSTRUCTIONS
Measure out the amount to be used in your tank. The recommended amount is up to 1.25 cups per every 100 gallons in tank volume, or 2 tablespoons per every 10 gallons of tank volume. The recommended method for use is in a mesh filter bag.
MESH FILTER BAG
Add carbon to your fine mesh filter bag. Rinse the carbon under water from your tank or RO/DI water about 30 seconds, or until the water runs clear. Avoid grinding the carbon in the bag while doing so, since this may create a fine particle dust that will need to be rinsed out. Place the bag into your sump or a high flow area of your tank to ensure water is being filtered well through the carbon.
MAINTENANCE INSTRUCTIONS
Remove carbon after 3-4 weeks based on tank needs and water clarity. Use as needed.
To determine when to add new carbon, a quick method to use is a bucket test. When doing a water change, add tank water to a white bucket, and compare to fresh RO/DI water in another white bucket. If a yellowish tone is observed in the tank water, add carbon as indicated above.
If an accurate measurement for when to use this carbon is desired, an ICP test with values indicating dissolved organic carbon (DOC) levels can be used. For example: SAC254 on an ICP-MS test is an indirect measure of the DOC levels. Do not use if DOC levels are below the optimal ranges, as this may adversely affect coral growth.
