halide upgrade-need help!

[bv_reefer]

well i currently have a great oppurtunity to upgrade my lighting from 2x70-watt hqi's, to a 1x400-watt. Again this is for my 33-gallon. I'm really nervous about it because it's a jump from 4.2watts/g to 12.12watts/g. But the absolute last thing i need is all my soft corals and lps bleaching from it, what can i do to avoid bleaching or shock. where and how high should the bulb be from the surface of my water, my current bulbs are about 5'' from the water surface. any suggestions greatly appreciated-

[michika]

For starters hang your new 400w bulb higher, say 10". You can slowly over time adjust it lower. You can also try multiple layers of mesh and remove one layer at a time over the course of a few weeks.

[bv_reefer]

so you think that by hanging it about 10''-12'' from the surface, my corals won't bleach? is hanging it high enough or will i have to put layers of eggcrate or mesh too?

[michika]

You may want to do both, and you can also consider reducing your photoperiod.

[bv_reefer]

my photoperiod is currently 12 hours, from noon to mid-night, so i think i'll start by hanging it 12'' abover water surface, couple layers of eggcrate, and reducing photoperiod to 8 hours to start, thanks again

[Reefer Rob]

8 hours of 400W is a lot of light (especially for a 33 gal). I think that should be your max! You might get away with more with a 14K or 20K bulb. I would start with 4 hours or less and work up slowly. Keep a close eye on your corals, and be ready to dial it back if you see any distress. Do you have a chiller?