Well,

I tried this combination front to back:

Purple +
Aquablue special
Purple +
Blue +

it was a bit to white for me so then i tried:

Purple +
Blue + (my old bulb)
Purple +
Blue +

and i think we have a winner! a lot more blue and red spectrum!

here are some pictures i tried to take, don't mine the messy algae everywhere, its because my bulbs were so old and i am finally changing them lol.

all bulbs on:
DSC 0324 - need some t5 bulb choice help

bulbs 1 and 4 (notice the blue in the back area and redish tint in the front:
DSC 0325 - need some t5 bulb choice help

bulbs 2 and 3:
DSC 0326 - need some t5 bulb choice help

i am going to mess around now and change it to:

Blue +
Purple +
Purple +
Blue +

that way the purples are on one ballast and the blues are on one ballast and see how it looks, back ina few!