In my 50 gallon tank:

substrate: 1 1/2 garden soil topped with 2" of the smallest gravel i could find.

light: 1 - 28watt slim t5 6500k

        1 - 20 watt t8 light that gives off a pink light

fish: neon tetras: 18

       a platy and a black molly

       an angelfish

       4 danios

plants: a few amazon swords and dwarf sags

i don't know what's happening, really. just a few weeks ago the the plants where growing well but not significantly. the sword where melting some leaves but also new leaves where shooting out at the same time so i wasn't too worried. but just today i noticed that the swords leaves are growing differently. they're leaves are becoming more narrow and and long very much unlike the leaves they had when i bought them and also more leaves are melting away. what could i be doing wrong? what should i do now?