I disagree with your statement, 'excess' nutrients never cause algae. The whole concept Of E.I fertilisation is based on this fact. IN practice very few tanks nutrient levels 'bottom out' Except for a few nutrients such as N. If all nutrient levels were to bottomout this would lead to bad plant growth. You know what that leads to? Algae. Provide most nutrients in excess so you can rule out the possibilty of nutrient deficient

Lots of healthy fast growing plants are the best against algae. Limiting Nutrients so you never have 'excess' nutrients is an old and dated method that does not work. focus on healthy plant growth.

Adjust ONE parameter and then kill all the algae by using hydrogen peroxide. introduce amano shrimp, and wait two weeks without changing anything, if the algae comes back kill with hydrogen peroxide,and adjust another parameter.