Brightwell Aquatics PhytoGold-S 250ml 4 - 10µm Phytoplankton Suspension for Soft Corals, Clams, Sponges, and Other Filter-Feeders Overview Provides phytoplankton ranging in size from 4 - 10µm. Ideally-sized for many soft corals, clams, sponges, tunicates, tube worms, and larval invertebrates. Dosage: 5ml/200l/day