It's a debunked myth that nitrate and phosphate are direct causes of algae. EI dosing is a form of fertilization than can use super-high concentrations of both with no issues.
Algae is an imbalance between lighting, CO2 and ferts. Not just nitrogen and potassium.
MamaFish: what are the dimensions of your tank? What specific lighting do you have? How are you fertilizing the tank beyond Excel? That will allow others to help you resolve your algae issues.