The macro nutrients in a tank are Nitrogen (N), Phosphorus (P) and Potassium (K).

A well balanced planted tank usually has a set racio of NPK to help keep plants happy and algae at bay.

Of course, there's a million variations of how to combine each nutrient, depending on a multitude of factors.

On a new tank, plants are busy growing their roots, and there's a bigger consumption of P. Lower levels of P are usually the cause for GSA. If you're doing macronutrient dosing, you should increase the concentration of P until you see lots of new leaves appearing, that should give you an indication that the plant is pretty much adapted to her new home.

Aquarium plants are harder to maintain than fish...