MH flicker but won't start

[Palmer]

Hi there

I came back from vacation and noticed one of the 250W MH bulbs was not lit. In trying to restart it the bulb would start to light but then fade out. Other bulbs do the same thing. The other side works fine. It's a maristar fixture with galaxy ballasts. Is this typical when a ballast goes downhill? Both the fixture and ballasts are 3 years old.