One side of hids has changed color

[hypnotized]

The passenger side of my hid set up has changed from 5000K to more of a purple colour. Does anyone know if that would be a ballast issue or is the bulb about to go?

[midnitehour]

bulb

[ejaz89]

the bulbs usually lose gas over time and tend to change color.. usually they change gradually that u don't notice them till long after.