Plants' requirements definitely differ from one another. Also, even if you have the same plant as someone else, you may have different requirements due to lighting, CO2, amount of fish poo, substrate, etc.
I've grown HC just fine using only high light and CO2. However, I bought the Pfertz line to deal with the green spot algae all over my glass and have been dosing 1.5 pumps of phosphorous daily in my 30 gallon tank. My HC carpet has doubled in size and thickness in about 2 weeks time.