Directions Shake bottle before using. Add 20 drops per gallon or 2 tea-spoons (10 ml) of its per each 10 gallons of water. Repeat dosage after 24 hours. Exact dose is not critical. Repeat above steps every two weeks or whenever unwanted organic debris or sludge is present. Freshwater Natural TidyTan Improves water quality - naturally reduces odors contains only beneficial bacteria breaks down organic debris in gravel and filters removes sludge from substrate does not affect pH Features Pack of - 12 Capacity - 4 oz. Dimension - 1.5 x 1.5 x 4.5 in. Item Weight - 5.1 oz.