I don't like the green I wanna get a light blue anyone know what size led I need ?

There are a lot of write ups on it. Take some time to search, I think theres a thread in the DIY section. I believe the bulb size is t3 or t4

The clock uses a vacuum fluorescent display, you can't replace a bulb to change the color. The best that can be done is placing a color filter over the display.

Oops, he said clock