The ZipGrow Matrix Media™ Replacement for 5’ ZipGrow™ Towers comes in two pieces for ease of loading. This proprietary material has massive biological surface area and high percolation for great performance in aquaponic systems. Replacements are slightly oversized to give the material a longer use cycle in ZipGrow™ Towers. Material is a black color for algae control and is compatible with the use of redworms. Lasts for more than a year of continuous use.