250W DE over 30" depth?
 

Just curious if anyone has tried 250W double-ended over 30" of depth (height) on a tank? Was it a bit of a stretch or was it fine?

I think it really depends on what you wish to keep near the bottom.

Down at the bottom, not much. Mostly I'm concerned about how much contrast there will be between the bottom and the top. It may not look all that great if the edges of the tank look dark compared to the top of the bommie which will be in the centre of the tank (this will be a cube tank).

I have a 250W DE over my tank with a depth of 24". There is definetly not a noticeable difference in contrast. But for a 30" depth, it maybe different.

Maybe a 400W HQI will be a better option :razz:

What's a Bommie :question: :question:

I would define "coral bommie" as something along the lines of "a tower-like coral structure sticking out from a sandy bottom." I thought the term was universal, but after a quick google search it seems I find it mostly in use in the context of the Great Barrier Reef; thus, it might be more of an Australian slang term, but on that I'm not sure.

Ah .. well, a 400W would go nicely over this tank. Ordinarily I would just use a 400W and be done with it, but being that this is a second tank I want to limit the wattage to 250W for the sake of trying to keep the utilities bill somewhat less offensive.

One alternative to the 250W DE over this tank I was maybe thinking about was just a 250W SE and a Lumenarc 3 (or Lumenarc 3 mini) reflector.

i run 2 - 250 and 1 400 [ se bulbs ] over 30" in depth and the have no problems , tank is mostly sps , 400 is brighter but their are no dark spot

hth -Russ

SE XM 250w 10000k bulbs have pretty high PPFD on an m80

I ran 250w DE on my 30" deep and I can tell you that the bottom 10" is not great for SPS colors, and growth is minimal. Having say that, I ran 20K bulbs on eletro ballast. I would imagine that 10K would suffice some SPS at that level. If it's just one lighting fixture you running, I'd go for the 400w.

Will, didn't you switch to the Lumenarcs?

BTW, some background, this isn't for an SPS tank, so I'm not too worried about SPS colour. I'll probably put some of my LPS on the bottom (they don't need a whack of light anyhow) and some of my less offensive softeys (gorgs etc) along the sides of the patch reef. The top real estate of the bommie will be the prime real estate and that's reserved for my ritteri.

So I'm kind of thinking that maybe 250W DE is something to try here. I'm still just a little unconvinced that it will be enough though... I dunno. Don't really want to go to two lights, at that point maybe just a single 400W is better after all. :eek: :confused:

Tank is a 115g cube (30"^3).

I think I'm at 28 and no problems.

Dave

reply
 

Bob asked Here is mine at 24 inches deep with a 14K 250 watt MH. I have recently upgraded to a 400 watt 10K. Tony, I'd go with a 250 watt 10K for added intensity for a 30" deep tank.
http://www.canreef.com/photopost/dat..._aug_small.JPG

I would say a 250W 1000K DE lamp would be adequate. I run a 150W 10000K on a 24"X18"X18" tank, and have complete coverage. This is with an Aqualight Pro so the bulb is about six inches above the tank. I just took a reading, and I get 3000 LUX right at the bottom of the tank. I get 7000 LUX at 15 inches from the top of the tank. At that point there is a Staghorn coral with nice blue tips..
This leads me to think that a 250W lamp should do well. :mrgreen:

I don't know what difference in output there is between SE and DE bulbs, but I'm running 2 x 250w 10,000k SE bulbs on Icecap ballasts with 2 x 96w PC actinics over my tank which is 32" deep. With the sand bed and the top rim, the water depth is about 28", the lights are about 8" off the water. I try to keep my SPS up higher on the rocks, but I have a plate coral and an open brain down on the sandbed. Both have been doing quite well and have grown noiticably since I got them about a year ago.

I can simpathize wanting to keep the utility bills down, my lights use plenty as it is.

How far up is your bommie going to go up? If the ritteri is going to be near the top half of the tank, I don't see a problem with a 250w MH... SE or DE. I hear really good things about those lumenarc pendents, I'm pretty sure one of those will be more than enough for a 30" square area. Since you said yourself that this is a tank for your ritteri, light doesn't really need to penetrate that far down.

-Rich

I just came across how J&L rates the MH units for depth
http://www.jlaquatics.com/phpstore/s...category_ID=70