SPS, MH and bulb distance

Aquattro · #1 02-09-2011, 05:07 AM

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?

lastlight · #2 02-09-2011, 05:17 AM

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

lorenz0 · #3 02-09-2011, 05:18 AM

150 de and it's 8-9 inches

Delphinus · #4 02-09-2011, 06:51 AM

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.

ScubaSteve · #5 02-09-2011, 06:59 AM

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).

gobytron · #6 02-09-2011, 02:09 PM

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.

reefknot · #7 02-09-2011, 02:33 PM

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

Trabby · #8 02-09-2011, 02:35 PM

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

Aquattro · #9 02-09-2011, 02:55 PM

Quote:

Originally Posted by reefknot

I have got 2 x 400W mogel base MH set at 17 " above 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!

lastlight · #10 02-09-2011, 03:49 PM

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.