Vallis issues

I can't seem to grow vallis in my 72 gallon tank. The light is(I believe) 2 watts per gallon and the light is marine blue antinic(?spelling) mixed with normal white, producing a very clear white color. Water is hard and alkaline, for I'm planning on keeping species from Lake Tanganika.

Before, I kept duboisi and julies, and they seemed to bite off the leaves around the middle, leaving the rest very ugly and ragged-looking. And the julies uprooted some, but they seemed to survive(Barely rooted, floating around) until I ditched them.

This time I'm going to use the same setup, but as a grow-out for some baby frontosa. As they are babies, I'm sure they won't try to uproot them, and would never eat them.

Could it work this time?