help me ID this plant?

Hau kolas..came across this in an unlabeled tank at a LFS about a month ago, threw it in my quarantine tank to see what would
happen. Woman who worked there who usually knows her stuff could only say it "needs high light" and thought it was hygrophila
polysperma 'sunset'. Hadn't seen it before or since. Well since then this plant has done very well. it's doubled in size,
colored up beautifully, and thrown out roots from the nodes like mad and is threatening to grow out of the tank..rapid growth
has paused at the water line for the present time. I'd like to propagate it, but don't want to kill them in the process.
here's some pictures, not the best quality in the world. doesn't seem to have the vein coloration of 'sunset' from pictures
I've found. the plant started off fairly green with maroon undersides of the leaves. , after going into the quarantine tank
with 65W over 20 gallons, the leaves became more true red, but the upper leaves are pretty much bright pink on the undersides
now. Any guesses as to what it could be? Or regarding propagation? TIA for any help

http://home.comcast.net/~farthunder/plant1.jpg
http://home.comcast.net/~farthunder/plant2.jpg
http://home.comcast.net/~farthunder/plant3.jpg this shows the plant appearance when first put into my tank
http://home.comcast.net/~farthunder/plant4.jpg undersides of upper leaves..more pink as approach waterline
http://home.comcast.net/~farthunder/plant5.jpg tops of leaves green tinted red

lila pilamaya