JBL Mandao Dark is a dark natural substrate with a grain size of 1.5 - 2.5 mm for all frehs water aqauriuums. Its porous structure promotes the growth of roots. Suitable for digging fish. JBL Manado Dark has a nutrient buffer with high iron content. Is capable of storing excess nutrients, to release them again when needed. The high iron content is absorbed by plant roots. JBL Manado Dark activates the soil flora by motivating the quick and effective colonisation of beneficial ground bacteria. This inhibits the growth of unwanted algae, reducing the work-load on the filter and ensuring crystal-clear water. JBL Manado Dark accentuates the beauty of the fish: ist dark-brown tone highlights their colours and combines with the green and red tones of the aquatic plants to create a harmonious appearance. Ready-to-use substrate which needs to be rinsed once in tap water before use.