• Rapidly removes phosphate & silicate
  • Ferric oxide coated aluminum oxide phosphate adsorber
  • High porosity and surface area give it a large binding capacity


Comparing Seachem Phosphate Removers
PO4 bound
PhosGuard (Alumina Oxide) 0.87 mg/g
PhosBond (GFO and Alumina Oxide hybrid) 1.19 mg/g
PhosNet (GFO) 1.41 mg/g

PhosBond™ is a revolutionary new product that combines the phosphate removing capabilities of both aluminum oxide and granular ferric oxide into a singular material forming a synergistic effect. It rapidly removes phosphates and silicates from saltwater and freshwater, combining the best of both types of phosphate removers. Its high porosity and surface area give it a large binding capacity, while its physical strength and integrity assures that it will not break down from mechanical stress.


For best results, PhosBond™ should be rinsed before use and placed so as to maximize the flow of water through it but not so that it tumbles against itself in flow. It may be used in a canister filter, media chamber, box filter, or any high flow area of a trickle filter. Use of a filter bag such as The Bag is recommended.

Use 60 mL (1/4 cup) for every 200 L (50 US gallons) saltwater or 400 L (100 US gallons) freshwater. Leave product in place for 4 days, then test phosphate or silicate concentrations with either MultiTest Phosphate or MultiTest Silicate. If the concentration of the component you are trying to decrease has not dropped to around 0.02 mg/L, then replace the PhosBond™, otherwise leave in place until levels begin to climb again. As long as concentrations remain under control, the product is not exhausted. Over treating is not recommended. PhosBond™ is not an exchange resin and does not release anything into the water. It does not leach phosphate or silicate back into the water and may be removed, dried, and returned to service until exhausted. Continuous use of small quantities is better than intermittent use of larger quantities.


100 mL, 250 mL, 500 mL, 1 L, 4 L

A: PhosBond Is best used in smaller quantities and changed frequently. In an environment with an excessively high phosphate reading, PhosBond will exhaust rapidly (4 – 5 days). Place the product in a high flow rate area and test your phosphate levels, changing as needed. When you see that your level is below 0.2 ppm (mg/L) leave that portion of PhosBond in the filter. Continue to test weekly for phosphate until you see it begin to rise again. You will then know that it is time to change the PhosBond. If you have low levels of phosphate the PhosBond will absorb the silicate in your system. It’s inert and safe to leave in your filter.

A: It is actually quite easy to change the apparent capacity of a GFO during testing. If the capacity of a GFO is tested at an extremely low pH with a phosphate concentration that is much higher than the media can completely, the media will temporarily absorb much more phosphate than it would under ordinary aquarium conditions. We have no interest in artificially puffing up our numbers, so the capacity we have listed is the amount of phosphate that the media can completely remove (without releasing back into the water) in a pH of 8.4.

A: We do not recommend it, as the tumbling action of a media reactor can cause this media to produce dust.

A: The main difference between these medias is capacity. PhosGuard has the lowest capacity at 0.82 mg/g of PO4 bound, but is the most economical of the four medias. PhosBond has a higher capacity than PhosGuard at 1.19 mg/g of PO4 bound, and combines the benefits of PhosGuard and a pure GFO (strength, high capacity, and rapid phosphate absorption) while still being very economical. PhosNet has the highest capacity of the Seachem phosphate absorbers at 1.41 mg/g of PO4 bound, and is a pure GFO media. phosfiltrum is a super-high capacity GFO (1.71 mg/g of PO4 bound) that produces very little dust. This media has a higher capacity than any other GFO on the market.

In recent years, there has been speculation that aluminum oxide based phosphate removers like PhosBond™ release aluminum into the water and subsequently damage corals. The evidence to support this claim was largely anecdotal.

So, through a series of controlled experiments in both freshwater and saltwater, we intended to address both the question of aluminum solubility and aluminum toxicity. The results of these experiments show that under reef conditions (pH near 8) there is no detectable soluble aluminum released from alumina. Under conditions of low pH and high dosage levels, soluble aluminum can be released from alumina; at three times the label dosage rate, we detected 0.2 mg/L aluminum at a pH of 5.3.

Additionally, aluminum oxide is not easily absorbed into the cell to cause negative reactions. Even at three times the dose, soft-bodied corals such as Sarcophyton remain unaffected.

For the full report on this study, click here.

A: Not at all! If it takes a phosphate absorber several months to reach its full capacity when the tank has high phosphates, it means that the media is exceptionally slow at absorbing phosphate. PhosBond needs to be replaced every 4 days as long as there is a phosphate problem because, given an infinite amount of available phosphate, PhosBond absorbs phosphate so quickly that it reaches its full capacity in 4 days. The 4 day replacement period is a function of how quickly the media works, not a function of how high a capacity the media has.

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1260 PhosBond 100 mL
1261 PhosBond 250 mL
1262 PhosBond 500 mL
1265 PhosBond 1 L
1263 PhosBond 4 L