Powerful Aquarium Water Purification Tablet,Water Purification Tablets For Fish Tank,Remover For Fish Tank,Aquarium Remover Name: Powerful Aquarium Water Purification Tablet Net weight: 35 tablets per bottle Shelf life: 3 years Usage Mthed: 1. First calculate the volume of water in the fish tank. How to calculate the volume ? Square fish tank: V (L) = length (CM) x width (CM) x water depth (CM) (measure the length / width / water depth of your fish tank) Cylindrical fish tank: V (L) = 3.14 x cylinder radius (cm) x cylinder radius (cm) x water depth (cm) (measure the cylinder radius / water depth of your fish tank) 2.2 Water Purification Tablets for 10L water,4 Water Purification Tablets for 20L water,6 Water Purification Tablets for 40L wateretc if the volume of water is 10L, then put 2 Water Purification Tablets to your fish tank, 3. After putting the water purification tablets, waitting for 3days,the water will be clear, if not , then put the water purification tablets again. Package includes: 1/2bottles *Water Purification Tablets For Fish Tank