The Swell Planted Aquarium Phosphorus is a fertiliser that contains phosphorus which is an essential macro-element for the proper nutrition of aquatic plants. If your plants don't get enough phosphorus, their growth will be stunted and it can also cause deficiencies of other elements as phosphorus plays an important role in the metabolism of the plants, without enough phosphorus, plant's can't absorb iron, sulphur and potassium.
To use Swell Planted Aquarium Phosphorus, add 8ml (1 capful, which is equal to 5ml) of the fertiliser to every 100 litres of water. This will raise the phosphate level in the aquarium by 0.05 mg/l. You can dose the fertiliser once or twice a week until the phosphate level reaches the desired range of 0.15 to 1.5mg/l, which you can measure using commercially available test kits. It is recommended to use Swell Planted Aquarium Phosphorus in combination with other Swell fertilisers in order to achieve the best results.
Make sure to add the correct amount because if you add too much phosphorus into the aquarium, the levels of phosphate can become very high, which can lead to the growth of brush and brown algae, which are fairly difficul to remove.