Made From Pure Rosemary And Clove Botanical Extracts 203 repels and kills Root Aphids, Fungus Gnat, White Flies, Gnat Larvae, Thrips & more. 03 has active ingredients that cause pests to dehydrate and die while also, attacking fungus and algae, reducing the food source for pests. SNS 203 can be mixed with SNS-209, SNS-604A, SNS-604B