Description: Kent Zoe is a superior vitamin complex for Freshwater fish and plants. (Zoe does not contain phosphates as most competing vitamin supplements do, and will not causeunsightly algae growth!) It contains aquaculture grade vitamins, meaning that they are still active after one year in your aquarium! It is unique because it also contains natural minerals from spirulina and kelp sources. Competing products arepreserved with glycerin, which is an alcohol and requires 50% concentration to preserve. Zoe is properly preserved, using less than ½% preservatives, yet has a 4 year shelf life with no refrigeration. Just smell thedifference