Hi,
The EI (Estimative Index of Dosing) method says that for a 20 gallons with 5.5 watts/gal the dosing will be:
1/4 teaspoon of KNO3 4x a week (every other day)
1/16” teaspoon of KH2PO4 4x a week (every other day)
Traces added on off days as the macro nutrients, so 3x a week, 5mls each time...