New Mariner: there's nothing wrong with your tank. Plants need nutrients to grow and with all that light they are starving, for CO2, nitrates phosphates, potassium and micros. Light is to plants as excercise is to us. They're exercising but they're not getting anything to build on. Changing your light source won't make anything better.
The best thing you could do for your plants is CO2,and start fertilising.
FILSTAR Pimp #2
75 gal heavily planted,50/50 Black beauty,Eco-complete substrate, Pressurised CO2 with solenoid, ph controller, AB Reactor 1000, 330 watts 9325K GE PC lighting,Ehiem Liquidoser, 2-Filstar xp3 canisters.