Flourite Dark, 7 kg / 15.4 lbs The Premium Substrate For The Planted Aquarium Providing Essential Nutrient To Plant Root Structure Long Term For Success Planted Aquariums Specially Fracted, Stable Porous Clay Gravel For The Natural Planted Aquarium Its appearance is best suited to planted aquaria, but may be used in any aquarium environment Never Needs Replacement And Remains Effective For The Life Of The Aquarium Not Chemically Coated Or Treated And Will Not Alter The Ph Of The Water