Iron-based media is supposed to be the best phosphate binder. There are several of them on the market today. They include ROWAphos, PhoSar, Ultra Power Phos and a few others. Based the fact that the FRITZ product is Aluminum-based and also binds silica, I would not use it. If you do attempt the FRITZ Phosphate Remover, please post your results for the benefit of others.
The aluminum dissolves and irritates corals as described in this article:
Aluminum and aluminum-based
phosphate binders
http://advancedaquarist.com/issues/july2003/chem.htm