Your HC seems to be doing very well. I honestly can't see the algae so that's probably a good thing
. Easier to see in person i'm sure.
The color of the lighting (from what I think) doesn't really effect the plants. I think the K rating is personal choice. It might have a little effect but I honestly don't know for sure.
It's just the normal color is around the 5-7000K rating. Then saltwater you want brighter color and such so you get the 10K. The lower colors just show more natural type light. The yellowish color might actually be cool for a natural look, but if you want to show off your true color of your plants you'll want to get a new bulb.
I am using two 15W CFL 6700K bulbs on my 5G Nano planted. Very pleased. Got them in a 2pack at wal-mart.
Can't wait to see your HC fill in and your hairgrass grow taller in the back.
You planning on putting any moss on that piece of wood or just leaving it?