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.

My 250w SE bulbs are about 8.5 inches from the water. They are in DIY Lumenarcs. I use plastic chain to suspend the fixture from the ceiling. This allows for relatively simple height adjustment by using a different chain link in the ceiling hook to raise or lower the assembly. Just need to make sure the chain is robust enough to handle the weight and so far so good for me. Might be able to rig up something similar inside a hood with a shorter length of chain. May not be as elegant a solution as an elaborate sliding or even automated rig, but on the plus side, it's simple, inexpensive and easy to set up.

http://public.blu.livefilestore.com/...66a.JPG?psid=1

I only have a couple of small SPS frags at the moment, so can't really provide any useful info as to growth. What I have is doing well. Down the road I'll definitely be looking at LED lighting to replace the MH.

I have one 250 Watt MH that's somewhere between 6 and 8 inches off the water surface. I have but one SPS that's probably only 8 to 12 inches under the water and it's doing great, so far.

I"m running 2x250W moguls about 8" above the water. SPS is doing great all different levels. I'm debating getting cheaper bulbs and adding a third ballast because it's a little too intense right now in some area's and i'm running out of shady room to put some not-as-high-light SPS.

mine were 6" above the water.. that was the majority from that old poll if I remember that far back corectly.

is there a way you could put them on a slide inside so you could lift them when yuo have to be in there? well I am sure there is if there is room in the canopy. I might be able to give you an idea when I come down at the end of the month.

I had mine on drawer slides so they would slide out the end when I needed to work on the tank.

Steve

I think mine are just too close for the corals. The tops of the rock towers just get blasted, to the point it's distracting to look at. With the new reflectors, I think they should be up another 3 or 4 inches. But do do that, I need to probably at least build new sides for my canopy :(

what about surface mounting them on the top of the canopy? this will also allow more of the heat to be radiated into the room instead of staying int he canopy.

I've got the canopy well vented now, with the ability to pump the air outside if I need to. Dispersing the heat into the room as you stated might make it a bit too hot around the house, if you know what I mean :)

Reviving an older thread. I have my lights about 6" off the water surface. 400W DE and after talking with Lance and looking at some other threads I think they are a bit too low. I'm proabbly going to raise them up to about 12" or so

I'll pitch in; I don't have a lot of SPS experience but passing on info that I read (and am currently using as a guideline) my single 250w DE bulb is currently 12-14" off the surface, with the bottom of the fixture about 6-8" up. Like others my fixture is suspended by chain that allows for about 6" adjustment to accomodate varying light levels as the bulb ages. I try to keep a minimum of 12" between the bulb and the water surface to minimized the amount of heat that ends up in the tank. With the pheonix 14k bulb in my DIY fixture I get about 40000Lux at the surface, about 13500Lux just into the water, about 8,000 mid-tank and about 4,000 at the bottom. My tank is 24" tall.

I have 4 x 250 watt about 6" above the water. No problems at all, I have corals 5 inches under water and they're doing great

225g: 15" from the bulb (400W 15K)

90g: 8" from the bulb (250W 14K)

3 x 250W SE shielded, ranging from 11.75" to 3.5" depending on whether I remember to pull the light rack back down after working on the tank.