Tropica Specialised NutritionSpecialised Fertiliser is added each week when the water is changed. We recommend 5 mL per 50 L water. However, we recommended that this is set in accordance with plant requirements. Specialised Fertiliser contains, in addition to micro nutrients, all essential macro nutrients. The fertilizer is particularly suitable where plants display a lack of nutrition. However note that if algae growth starts, Specialised Fertilser will promote this growth.