I have 6 of them growing in my 55g tank. I love that plant and they add
red variety to the greens of the other plants. I have a couple who do
not have there bulbs and they grow as well as the plants with bulbs. It
could be that you have to much light for it. Mine grow with under 1wpg
using the NO lights that came with the tank and full spectrum deep reef
10,000K, 15W bulbs.

Vicki