[mfrumkin]

The phosorb bag broke open and a certain amount of the media went into my 15 gallon reef tank. We did a 50% water change but some of it is still in the tank. How harmful is it to the tank?

[Ninong]

What is phosorb? I assume it is a phosphate sponge product but what is it? Do you know? Is it alumina based or ferric oxide hydroxide based? What color are the granules?

Who makes it?

Water changes are not necessary and wouldn't make any difference anyway unless you actually remove the product with the water. I doubt that you have a serious problem but it would be better to get it out of there. If it is alumina, it will gradually dissolve over time and raise the aluminum levels in the tank to a point that could be detrimental to leather corals and some other invertebrates. I have no idea exactly how much of this stuff has gotten into your 15-gal tank, so it's hard to say if you will have any sort of problem or not.

If it is iron based, I guess it will gradually degrade over time but it shouldn't cause any real harm.

[mfrumkin]

This is all I can find on the product,

"Phos-Zorb, from Aquarium Pharmaceuticals Inc. (API) is an aluminium oxide resin designed to remove phosphates and silicates from aquarium water."

Unfortunately I don't believe there is anything I can do but hope for the best.

[Ninong]

Aluminum oxide would be Al2O3 (aluminum trioxide), otherwise known as alumina. Most manufacturers have switched away from that in recent years in favor of ferric oxide hydroxide. Tests by Dr. Randy Holmes-Farley, chemistry forum moderator at Reef Central and vice president at a large biotech company, have shown that alumina actually does leach toxic aluminum into saltwater over time. It is a very small amount but some invertebrates, leathers in particular, are sensitive to a very low concentration of aluminum.