New MH Probs?

[T4Stock]

Hi there. I am new to SW tanks, and I have a question about my replacement MH bulbs. I just installed two new 175W MH bulbs to replace my old bulbs (which are working fine). Problem is, the new bulbs won't light. I now the sockets are hot b/c the old bulbs light right up.

Wuz up wid dis?

 

[davelin315]

Sometimes it just takes time for them to fire up, or you could have a problem with your ballasts.

 

[cubera]

What are your new lamps and what were you using before? This situation seems very odd to me.