Reflector for 36x36x25

Thought about upgrading to a 36x36x24 and trying out Mh instead of the T5s I use know on a 40g breeder. Tanks going to be mostly SPS. Wondering if a single 250w would be good. If so what would be the best reflector to do the job?
Figure on having most LR and corals near the center so the fish can swim all around the LR island. But everyone knows how it is when placing rock. So who really knows

Thanks

 

Can't really answer your question, but I do love cubes.

Honestly, I would think that would not be enough, but it would depend on what your rock work would be like... how much.

I never had them, but once I saw them on other's tanks I understood what all the fuss was about. Have you considered one 400w SE Radium 20K? Very nice color. I know Radium has been working on double ended and 250 w.. can't tell you how that has turned out, but I thought the SE 400w 20K was PERFECT.

Various quality reflectors to do the job, can't recommend one in particular, but I think it would be a good amount of light.

 

Hum. Kinda forgot about 400w lamps. A while back i was looking into a 48x24x24 for like forever and was going to do 2 250w for it. But just started thinking a cube might be more acceptable by the wife and still look killer.

So what kind of heat would I be looking at with a 400w? Would I be look at a chiller for instance?

As far as aquascape goes. I'm kinda into the less is better group and I like the columns style look. I'll have alot of LR hidden in the sump area though.

Ugh idk might still consider the four foot tank instead. I have a good spot for both.

Your thoughts?

 

Hard to say. I'm a fan of wider tanks and like those 120s too. As far as heat... it isn't as simle as saying this light will require this cooling... there is so much more to it as far as what all your heat imputs are and what are your losses.

I had a chiller on my 90g with 2x150 MH... I swapped them out to 2x250 and took the chiller off cause I did other things. A small fan works wonders. Yes you have to top off more.. but it is pretty easy to get by without a chiller. 500w over the 120 isn't going to be much different that a 400w over the cube.

 

With the 400w do you think I could go deeper then 24 inch and still do a full sps tank? Say somthing like a 30" ? Ah prob stick with a 24 simple because I want the light up a high as posable. Just so I can get the full effect of the rimless tank and less heat.

 

Ya... that's really it. My light was pretty low, but I moved it up a bit like 8 inches I think and it made a big difference. And again... there really is no such thing as this light will go this deep. PAR is going to drop the deeper it is no matter what. So it depends on what you start with (8K... 20K) and what you put at the bottom. And there are those deep water SPS that live in those conditions.

At least in this application... a cube, one light does well and a 400w Radium 20k would be sweet if you like that look.

 

A single metal halide will generally not light more than a 24"x24" area well. This is the way the reflectors are designed. Something like the lumenmax reflector may do 30"x30", but the wider you go, the less PAR you'll have. From any given light, you have so many photons per second. PAR is basically photons, per time period, per area. If you spread the same amount of light over more of an area, you get less PAR. So, for a 24" deep tank, generally we say that we want something like a 250W MH to "punch" down that deep. However, that's assuming we're trying to cover an area 24"x24" or less.

So, let's do some simple math. If we have 24x24, the area is 576 square inches. If we have 36x36, that's 1296 square inches. So, that's 2.25 times the area, so, PAR with the same bulb, should be, on average, about 44% of the PAR over a 24"x24" area. To get the same PAR over a 24"x24" area, over a 36"x36", you'd therefore need about 563W of metal halides. However, that is assuming that there is a reflector that will cover a 36"x36" area well. And no one, to my knowledge makes a 563W metal halide

Also, though, wattage for halides is somewhat misleading. You can often get the same light output out of a 250W metal halide as a 400W metal halide. Blue metal halides are generally very inefficient. Often, to get the same PAR from a 250W 10000K (white) MH out of a 20000K (blue) metal halide, you'd need to go up to 400W and then you still may not get as much PAR. To get the same PAR out of a 10000K 400W, with 20000K, you may need to go to 1000W ect... So, wattage is only one consideration.

I think if you went with a lumenmax reflector, with a 400W, you could probably do okay, but you still may have some dimmer areas around the perimeter. That may not matter though, as most people don't keep SPS all the way out to the glass. If you want to go deeper though, you need more light. I think as your already pushing the limits, this may be a problem, as the next jump up is 1000W and you probably don't want that electric bill...

Here is a comparison of reflectors. Keep in mind, that they all have approximately the same reflectivity. So, lower PAR, generally means that it is spreading the light out more. You want something that spreads it out a lot:
http://www.reefcentral.com/forums/showthread.php?t=1664775

Also, here is Sanjay's reef lighting guide. You will need a bulb/ballast combination that produces high PAR. Most of the high PAR bulbs will be yellowish though, which may not be desirable. You probably want to find one with a higher "K" rating (bluer) that still has high par (ppfd).

A 400W on a magnetic ballast may be one way to go, as the magnetic ballasts, while using more electricity, also produce more PAR. You can see here though:
Manhattan Reefs - Sanjay's Lighting Guide

 

A lumenmax elite should be enough for day time light. You will need either a 2 bulb actinc (t5) with moon light leds or something life a panoroma led strip

 

Yah I read that article all time ago Lumenbright Reflector comparisons - Reef Central Online Community
Good review. I read it.back when I was going to do the 4 foot tank. At the time I was going to go with 2 250w LB mini's. But know I'm leaning more fords the 36 cubed tank. So back to square one

So I wonder the review said that " all four reflectors covered the 36" area well"
So does that mean that their wouldn't be a dark ring around the outer edge of the tank?
Know I know that the par wouldn't be much at the edges but what kind of good growth area would I have? For enstance he had the lamp about 15" above the floor and thats about how high I want my lamp or lamps. At that hight at dead center under the reflected the par was very high but what kind of radius can I expect good enough par for sps? Know I know at some point from center the par is going to start to drop. any idea as to where that point is from center and how dramatic is that drop?

Reason I ask is, just like M2434 posted I don't plan on having corals growing on the outer edges of the tank. I plan on having a single column or 2 somewhat close to the center of the tank. not alot of LR in the display. At the same time I don't want it to be black around say 6" from the glass all the way around the tank.

Hope that made since.

 

Visually I think it will be okay. Our eyes aren't good at perceiving differences in PAR. Honestly, I doubt many people could "see" the difference between 100 and 300 PAR even. I think that's is more what Mark meant when he said they illuminated the target area well. Especially, deeper, it the the hotspot that will grow SPS corals. LPS and soft-corals can get away with less.

As for coverage, I find I have issues with SPS below about 200 PAR typically, although again it depends on the given coral. 300+ usually gives better coloration and sometimes growth. LPS and softcorals can often do well down to about 50 PAR though. So, if you don't mind mixing things, that works. Although, mixed reefs are tougher, for example flow requirements may be quite different. Depends what your looking to do though.