rbta growth

[Invigor]

I've got this rbta, and i've had it for about 2 months now..and I don't think it's grown at all since i've got it..it's under 400w of pc light and it's about 12" below the light...192w of lights are 1mo old, 130w of light are about 6mo old..
and I put 2 40w flourescents on for good luck

for the past 2 weeks i've been feeding it chunks of raw shrimp i picked up from superstore...it takes them and inhales them within a few hours..then goes back to normal

its tentacles are long and stringy and it shrivels up to nothing about every 2nd day...is there anything else I can do to help this thing grow?

i'm guessing since it's flourescent lighting it's not getting enough light.. :|

...would soaking the shrimp in selcon help get it more food?