Thanks for the replies guys. Sorry it took so long to reply, I have the flu, and accoding to the doctor, a bacterial infection as well. Yay.

The model tim is using, the three prong appliance ones (that if we are using the same tim, has red plastic trim on a white body?) that is the one that prompted the move to a digital timer, it stayed on, and because of my schedule i didn't notice for 2 days... that was about 5 weeks ago, I moved to Intermatic Model DT27, which is a digital self adjusting timer rated at 15 A (1800@) 500W Tungsten, 1/3 HP, 120 Volts, 60Hz.

That is the one that will no longer power up the 250 watt metal halide, and that is all that is was running. It may just be a fluke, as the other one is still running just fine.

Richard, are you adding to the list of stuff I need to buy for the new tank?