Artificial seawater has been used exclusively in this system. Of several proprietary and published formulae compared, only "Triton Marine Salt"(Triton Aquatics,Inc.,Levittown, Pa. USA,19057)30%. Heinle reported successful culture of Acartia in "Instant Ocean" (Aquarium Systems,Inc., Wicklifffe, Ohio,USA,44092) at 12% salinity. Acartiatonsa did not survive when this formula was prepared at the higher salinity of this system.