Replacing halide bulbs

[finland]

I have 2 - 250 watt halides that are about 12 months old. I have ordered 2 new 10k Ushio bulbs. They should be here tomorrow, and I was wondering if there is a big difference in intensity between the old ones and the new. What I am getting at is, do I have to acclimate the tank with a shorter photo period or maybe replace one right away and the other in a week or two. Or can I keep the photoperiod the same, replace both bulbs tomorrow, and not worry about it. I don't know, so, any suggestions would be appreciated.

 

[starfishjackedme]

You will need to acclimate your corals to the light. They will burn otherwise. I think the best thing is to raise them up a few inches if possible, then lower them back down progressively with time. I have fixtures independant of the canopy so i can take them out or move them, it helps. If you can't do that, i would only run them for two 2 hour periods with some time in between and then progressively close the gap over time to get to your target photo period.
Good luck and happy reefing!