Yeah we used Rowaphos in the beginning and didn't like it too much as it didn't get the job done at all..
Quite the opposite in my rig. Bulk Reef supply high capacity would last 10 days less than Rowaphos with the same agitation and same 3.5 cups. And I say last less, when it would register .04 out of the reactor outlet at about 16 days.
But hey, to each his or her own.