Pin by Amanda Moser on Robsessed? Yeah Probably! Twilight bella and Tropica Specialised Nutrition. Specialised 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. Specialised Fertiliser contains nitrogen (N) and phosphorus (P). Dosage must therefore be adapted to plant absorption rates, to avoid undesirable algae growth. Where signs of algae growth develop, reduce the dosage by 50% and increase water changing frequency by 50 %. Changing the water not only reduces the concentration of nutrients in the water, but also removes algae spores, remnants and other accumulated elements from the aquarium water. Suitable for aquariums with many and fast growing plants