New and Improved: Thrive Caps are a very similar product to the previous ThriveTabs, with a few improvements. These aquarium root tabs require no additives to make them stick together, a feature that allows them to be smaller and more concentrated while still delivering similar nutrient levels. In addition, contrary to ThriveTabs that caused clouding in some tanks, these new Thrive root tabs have an improved formula that manages to reduce the clouding effect. Thrive Caps are nutrient-rich root tabs for aquarium plants designed to be placed in the substrate of a planted freshwater aquarium. They will provide a long-lasting nutrient source essential for healthy plant growth. Thrived Caps are a blend of dry Thrive mix, ironrich clay, and mineralized topsoil which makes them the best root tabs for aquarium plants.