I think it will do OK. I doubt that you will have a lot of growth at 2 watts/gal. Xenia is strictly photosynthetic. It doesn't feed, and is thought to absorb nutrients from the water. Xenia grows like a weed under my MH at 6.5 watts/gal. but only slowly under VHO's at 5.9 watts/gal. in my other tank.

I think it has a lot to do with what spectrum bulbs you are running. I know it grew out of control under my 6.5K MH's, but then just about everything did.

Gary