spray a pattern which spreads more horizontally than vertically to fill in the liquid impeller layer more completely and to keep it from becoming too thick in addition to the supply pipes spraying into the liquid impellers preferably there are also drain pipes drain inlets 106 feed into drain pipes 107 which lead back to a central drain 108 which is distinct from the central supply pipe 109 an axial exhaust pipe 110 takes out the sink flow products from the workspace support frame members 111 keep the pipes and jets from becoming distorted or out of place and support floats 112 can relieve their weight a peripheral wall 113 sets a boundary for the photobioreactor fig1 shows a cross section of two liquid impellers in the photobioreactor the top liquid impeller 114 is created by jets from fluid such as water carried by main supply pipes such as at 101 fed by a central supply flow 119 creating an overall direction of flow 8 in this case the upper boundary of the upper impeller is equal to the surface of the water the bottom liquid impeller 115 is created by a similar array of pipes and jets but pointing in the opposite direction so as to produce an opposite direction of rotation 9 in the liquid impeller oppositely flowing turbulence 116 extending from the boundary layer into the shear layer in the workspace 11 creates a vortex network with a sink flow of lighter products 17 being drawn into the central exhaust while a flow of heavier products 15 flows from the periphery a network of drain pipes 107 is preferably also present leading into a central drain outlet 120 a support float 112 helps manage the weight of the pipes and.