welcome.i think you would need to buy a whole new blue light kit. i don't think you can just replace the bulbs. they are surrounded by the plastic tubing that doesn't open as far as i know.
I am looking to change mine to purple. Do you have it in that color?I sell the cathode kits for the tC.
How much and do you have it in purple?I sell the cathode kits for the tC.