i would think so--it would in my system, but everyone's system is different. i once read someone say that they added phyto until hair algae appears than ease off a bit...i've been working off that philosophy myself and it seems to work pretty well. i personally add about a capful a week (or less) and i have sponges, corals, gorgos and feather dusters all thriving. on the flip side however i also have flocks of peppermint shrimp always releasing babies into the water column which definitely helps the ecosystem. but if i were you i'd just cut waaay back, fix the algae problem, then ease back into it--assuming the dt's turns out to be the source of the problem, then you'll be able to guage how much you can add by what's the limit before you start to have algae blooms. make sense? please, also, let me know if this fixes the problem, i'm quite curious now! -leigh