First, this is incomplete and obviously from a novice so feel free to correct me.The 2 most common phytoplanton (macroalgae) are;Isochrysis Galbana (aka Gold Phytoplankton) is important for clams and scallops. I wanna say it is is different because something about lipids and fatty acids???Nannochloropsis Oculata (aka ~common~ Green Phytoplankton) this is likely what anything home grown is and what DT Phytoplankton is. It's useful for everything else specifically rotifers. Someone on Reef Central said it is the "weed" whereas Isochrysis is the bermuda/ buffalo grass of Marine Aquariums (not sure if that is true).Isochrysis Galbana is harder to raise for many reasons, 1 - it's color and 2- a shorter shelf life than Nannochloropsis.Supposedly true phytoplanktons; can not cohabitate because their defense mechanism is to release a toxin that would kill both.