Incredibly beautiful tank! I'm so jealous

This is truly one of the nicest aquascapes I have seen on here.
When you say you have a "plant grow" bulb, do you mean a NO fluorescent? If so, the Sylvania Gro-Lux bulb, the Penn Plax Aquari-lux bulb and the GE Aqua Rays bulb all have a very pink tint which would enhance the pink in your plants. I believe the GE bulb is 9,325k. But you're probably better off looking at the spectral graphs for color analysis - look for bulbs that peak in the red zones. Sometimes aquarists refer to these as "beauty lights"...see here:
http://www.liveaquaria.com/PIC/article.cfm?aid=25
I think the different color spectrums also have an impact on the way the plants grow. Red makes lower bushier growth, blue makes longer and leggier growth. Yellow and green tends to promote algae.
At least this is my understanding...I'm no expert