Seachem Phosguard is what I use.
Ferric oxide doesn't remove as much phosphate weight for weight compared to Seachem. Ferric oxide has a tendency to remove acidic organics at the same time so it's working as carbon in that sense not strictly a phosphate remover.
Is this product ran in a fluidized reactor ? Where do you get it ? And what level of Po4 (pm) have you been able to maintain with it ? Intrested for sure. Do you carry this at kee's?