I use Rowaphos in a reactor and still need Microbe-lift Phos-out 4 to keep the PO4 down under 0.05 Also nopox to drop PO3 to zero. I use Reef Energy ab+ to offset the ultra low nutrients. I am going this low atm because of a bad Green hair algae outbreak a few months ago,which I am slowly beating. (60 litre soft coral tank, 2 clowns 3 pyjama Cardinals)