Some questions about lighting...

[MikeP]

I'm upgrading from my two 175w 14k MH's to two 250w 14k (maybe 20k) MH's. Although it's not a huge amount of difference in wattage how should I introduce the tank to the new lights? I'm thinking just reduce the photo period and gradually increase it back to where it was originally. I'm also wondering about the mounting position of mogul base MH lamps. When I bought these 175w bulbs about a year ago (they have only been in use for 4 1/2 months) I didn't know there was different mounting positions. The ones I have now are horizontal mount but they are in a vertical position and so far so good. I just wanted to know why the mounting position matters.

Thanks for any info