SPS, MH and bulb distance
 

I can't find the poll/thread from years ago, so thought I'd revisit this.

for those running MH over SPS tanks, what distance are your bulbs from the water?

I run SE (no shields) and they are about 7" from the surface.

150 de and it's 8-9 inches

I'll have to measure to be sure since it's been a while since I hung the lights and I don't remember but my goal was 12" for the lamps (not the bottom of the reflectors but the bulbs themselves). Wanted a little more height for a couple reasons: reaching in with a hand without burning my elbow, heat mitigation, and better coverage/less shadows/less-straight-up-and-down-angles so that corals have some hope of side lighting since before with lamps closer to the surface I always had corals dieing out at the bottom and I really want to avoid that with this tank. I forget but there was a fellow out east with a similar sized tank to my own (was big on reefescape.ca when that board was still around) who went 12" and I sort of modeled my lights after his tank.

I've got a 250W Coralife about 4" above the water of my 40g, though I would like to raise it up a couple of inches to get better coverage (square tank).

I have my lights within 5" if the water surface...
I run 2 HQI 250W halides and sometimes I think the light is too intense in the topo half of my 24" deep tank as I often have new corals bleach out even if they came from a comparably lit tank.

I have been contemplating moving them up to around 8" off the water surface.

Looking forward to more hobbyist input here.

SPS, MH and Bulb Difference
 

Yet another thread that has caught my attention, so much wealth of info on this great site, thankyou everyone.
I am fairly new at this hobby and have just started to collect some SPS. I have a 48" x 30 " tall x 18" tank and I have got 2 x 400W mogel base MH set at 17 " above water, ( that is the bulb ) it gives good coverage and appears to reach the depth okay, I guess time will tell, lol I also run two T5 454
any hints or suggestions always greatly appreciated.
Kevan

We run two 250w about 8in from the surface of the water.

That seems a bit high. I run mine about 6" off the water, thinking of moving them up a couple inches, mostly to eliminate blasting the top corals, and giving myself a bit more room to work in tank without burning myself.
Keep us posted on SPS growth and color at that height!

I'd move mine up if it were easy to do. I had to cut back my lighting bigtime as things were bleaching even under the 20k. I think I'll be going about 10" from surface to actual bulb in the new tank. I'm trying to puzzle out a nice way that each reflector can slide up or down into position within the canopy so they are easy to adjust for lighting and for access.