Ultum Nature Systems Controbase is a highly porous, nutrient-rich substrate designed for planted aquarium use. Composed of pumice stone infused with slow-releasing Nitrogen, Potassium, Phosphorous and trace elements, it provides numerous benefits such as support for heavy root-feeding aquatic plant species and excess nutrient regulation. Its larger 6-8mm granule size promotes improved water flow and oxygenation, cultivating beneficial bacteria growth and improving plant vitality. Key Features Comes pre-bagged in mesh filter bags for easy removal and reusability. Can be stacked to create varying slope heights for aquascaping. Nutrients will last for approximately three months. Ideal touse with UNS Controsoil or Controsand, depending on your aquariums needs. Product Specifications UNS Controbase 2L Each BAG includes four (4) individual 0.5L mesh bags of Controbase. Aquarium Size:up to 20 gallons (UNS 60U Standard Rimless Tank) UNS Controbase 8L Each BAG includes sixteen (16) individual 0.5L mesh bags of Controbase. Aquarium Size:up to 114 gallons (UNS 120U Standard Rimless Tank)