My 46G bowfront holds about 35G of water and is heavily loaded with fish and I add nitrogen, 30mL/week to maintain +/- 20ppm.
Nitrogen deficient (stunted growth, Chlorosis, affects the whole plant)
How many gallons of water does your tank hold after filling with rocks and decor? Here is Seachems recommended dosing schedule.
Seachem Plant Dosing Chart.pdf