Metal Halide

[Aquascaper]

Hi,

I have a 150w Metal Halide running off an electronic ballast which has been fine for about a month. The past two days the halide turns off after approx. 15 mins running then requires a good 5 mins before I can turn it back on. I've tried cooling the ballast with a PC fan and now it never gets too hot to touch but the problem still persists

Any ideas as to what the problem is and how to cure it? I'm desparate as my corals are starting to look unhealthy already.

 

[Rooster]

Duff lamp or ballust ..... do you have another lamp to try ? If not, my money is on the ballust....