To use this tooll: Fill in your aquarium volume, select the chemical you want to use for each of the nutrient category then fill in the amount of each chemical.
You can also specify the method of adding the chemicals to the aquarium:

• Directly to the aquarium: In this case all the amount is added to the aquarium.
• Dissolved in a solution: This means you prepare a solution first, and then just add some of it to the aquarium.