I keep Seachem Nitrogen, Seachem Phosphorous, and Seachem Potassium on hand to cover the basic NPK macronutrients (also have Seachem Iron). I also keep on hand Seachem Flourish and Seachem Advance. I no longer use Seachem Excel. I add ferts based upon results from API test kits for Nitrates and Phosphate, Seachem test kit for Iron and Salifert test kit for Potassium twice per week in my 30 gallon planted tank. As as my supply of liquid Seachem ferts dwindle, I plan to migrate to mixing my own NilocG fertilizers to save $$ going forward. I already purchased and have on hand NilocG's 500 ml Dosing bottle, PPS Pro Aquarium Plant Fertilizer Package and Fert Scoop Dosing Spoons. In combination with CO2 injection, my planted tank has been doing well for over 1 year. The plants have been growing rapidly.