Optimal Orientation of MH Bulbs?

[GMGQ]

My tank is 70gallons, about 24x18x48. My MH lights are about 11 inches above the water surface, so I'm thinking of lowering them at least halfway. While I'm at it, I'm wondering if I should change the orientation of the bulbs/reflectors to get better coverage. What do you guys think about the following configurations?

Currently my 250W MH Moguls + spider reflectors are like this:

Left to Right:
http://www.auphanonline.com:8080/gallery/images/uploads/1/l_060614033356_432_1_4.jpg

What if I changed them so the tips of the bulbs are facing the front, so that the reflectors cover more area laterally?

Front to Back:
http://www.auphanonline.com:8080/gallery/images/uploads/1/l_060614033356_432_1_2.jpg

Theoretically it looks like I'll get better coverage from the reflectors. But how much light would actually be reflected, compared to the bulbs running 'along' the length of the tank?:

[Joe Reefer]

I am using the same reflectors, they are mounted perpendicular to the front like the bottom drawing. J&L also says they should be mounted in that manner. FWIW these reflectors work very well.

http://www.jlaquatics.com/phpstore/store_pages/details/lightparts.php?product_ID=pfo-prf12

[Delphinus]

Just a thought, but when I put my lamps in the perpendicular orientation, I made it so that the tips faced back instead of front, so that I wouldn't get blinded too too badly when I would go to feed the fish and so on.

As for orientation it generally depends on the reflector and the shape of the tank. For the ones that are recommended to go perpendicular, it is usually because the shape of the light cast is longer in one dimension than the other, and the shapes of most tanks is that they are longer and higher than they are deep ("deep" in this case referring to the front-to-back dimension). Thus, in a cube tank, say, it wouldn't much matter since the depth is the same as the width, so it would be six-of-one/half-dozen-of-the-other. Another consideration is that if you wanted to have actinics, it's usually easier to shoehorn everything in if it's all parallel.

Anyhow for a 48x18 footprint and Spiderlight reflectors, and no concerns about fitting the supplemental actinic (if wanted), then I would go perpendicular. (I notice in your drawing that the fluorescent tubes fit on the side anyhow.)

BTW what software did you use for those drawings? That's way cool!

[TheReefGeek]

No drawings are showing up for me.

Is your tank 24 high, or 18 high?

It it is 18 high, meaning 24" front to back, then each bulb is lighting exactly 24x24" so it wouldn't matter much.

I voted parallel because I don't keep much stuff right up against the glass, more stuff in the middle, so I wanted the bulbs running down the middle of the tank. This may be negated by a reflector, but my PFO reflectors are meant to run parallel so that iw hat I do.

[GMGQ]

Hah! Very funny that you mentioned about the "blinding" factor. Yesterday I was syphoning out cyano, and I couldnt take the blinding light anymore, so I put on my Oakleys! So this is a good point. I did think about it, but I was wondering... Whichever side the socket is, that area will get less light, right? Being the front of the tank is the deepest (no LR, just the sandbed), I though that it would be best not to have the socket on that side? Or is it too negligible?

Just a thought, but when I put my lamps in the perpendicular orientation, I made it so that the tips faced back instead of front, so that I wouldn't get blinded too too badly when I would go to feed the fish and so on.

Yes, I currently have (2) 48" T5 Actinic+ bulbs on the front and back of the hood. Since my MH and reflectors are like the first picture now, I have to squeeze in the spider reflectors, so that the reflectors dont cover the T5 reflectors. That's another reason why I'm considering the 2nd picture.

The software I use is Maya by Alias Wavefront. It's the software Pixar uses, haha. (I took a 3D animation course before).


Anyhow for a 48x18 footprint and Spiderlight reflectors, and no concerns about fitting the supplemental actinic (if wanted), then I would go perpendicular. (I notice in your drawing that the fluorescent tubes fit on the side anyhow.)

BTW what software did you use for those drawings? That's way cool!

[Delphinus]

Alias Wavefront -- fabulous. I should have guessed. There was a time I was into designing 3d modeling techniques and animation and visualization although when then steady paycheque came with more mundane things I ended up not pursuing that career line (although there are days I still regret that .. oh well).

I was watching Cars on the weekend and in the opening there was "Pixar - Celebrating 20 Years" and suddenly I realized-- Oh my God-- I'm old.

The problem with Pixar is that they make all other animation films look .. well .. bad. :lol: They are awesome. And Alias makes awesome tools. There was a time I would have gone to work for them .... oh well, water under the bridge now!!

...

Anyhow, as far as less light making it to the front of the tank, I didn't really notice that myself. Mostly the shadow that's cast by the socket goes out horizontally anyhow, so no concerns about a dark spot in the tank or anything like that. Also you usually don't have anything right up to the front glass anyhow since that's your viewing pane, so I don't think it's a huge concern. Maybe try it both ways and see if you notice a difference but my guess is that you wouldn't really notice.

[Samw]

Assuming you have the PFO Optimal reflectors mentioned by Joe Reefer and will mount them at 6", I vote for perpendicular. If you have the parallel reflectors, then I would change my vote to parallel. If you have another brand, I would follow what the company recommends (probably parallel).

PFO Website from 2003:

http://web.archive.org/web/20030422170911/www.pfolighting.com/new+pfoAq/Retrofit+Items.htm


"OPTIMAL REFLECTOR(Reeflector): This reflector is designed to mount perpendicular to the front of the tank. It is made with 95% reflective aluminum and will put about 40% more light into the tank than a standard flat sheet of reflective metal. "


"PARALLEL REFLECTOR : The parallel reflector is designed to mount parallel with the front of the tank using fluorescents. It is made with 95% reflective aluminum and will put about 25% more light into the tank than a standard flat sheet of reflective metal. "

From Sanjay's Testing I Believe:

Light Distribution for Optimal reflector:
http://www.advancedaquarist.com/images/mar2003/fig10-pfo-perpendicular-top.gif

Light Distribution for Parallel reflector:
http://www.advancedaquarist.com/images/mar2003/fig8-pfo-parallel-top.gif

Using the optimal reflector at 6"-9" from the water surface, the area with the brightest light is greater along the X axis. Notice the shape of the oval near the center is wide.

Using the parallel reflector at 6"-9" from the water surface, the area with the brightest light is greater along the Y axis. Notice the shape of the oval near the center is tall.

Thus, at 6"-9" from the water surface, it is better to mount Optimal reflectors perpendicular to the tank and Parallel reflectors parallel to the tank.

At 12" from the water surface, it looks like both should be mounted parallel.

Info taken from:

http://www.advancedaquarist.com/issues/mar2003/feature.htm

.

[TheReefGeek]

Great info, didn't know about their Optimal reflector. Now I wish I had that instead of the parallel one! :)

[GMGQ]

Yes mine are the Optimal type. Thanks so much for this info! Definitely the way to go then.

Assuming you have the PFO Optimal reflectors mentioned by Joe Reefer and will mount them at 6", I vote for perpendicular. If you have the parallel reflectors, then I would change my vote to parallel.

[TheReefGeek]

GMGQ, where abouts did you buy the Optimal reflectors?

[GMGQ]

Haha, yeah man, A|W is awesome. But it's so true that it's hard to find a job in the field these days. In our class, one of my buddies Finally got a job at EA -- 3yrs after the course. He knew someone there, who got him interview after interview, and gave him tips and stuff. So he eventually made it in. Another friend is doing top secret models for a local company which is contracted by the US Army. So that's TRES COOL. I personally just do some freelance work for my other buddy's software company on the side. Speaking of Pixar, I couldnt believe the Toy Story 10yr anniversary DVD set came out last year :S I still love "Geri's Game" the best!

Alias Wavefront -- fabulous. I should have guessed. There was a time I was into designing 3d modeling techniques and animation and visualization although when then steady paycheque came with more mundane things I ended up not pursuing that career line (although there are days I still regret that .. oh well).

I was watching Cars on the weekend and in the opening there was "Pixar - Celebrating 20 Years" and suddenly I realized-- Oh my God-- I'm old.

The problem with Pixar is that they make all other animation films look .. well .. bad. :lol: They are awesome. And Alias makes awesome tools. There was a time I would have gone to work for them .... oh well, water under the bridge now!!

Yeah good point, I'm just over thinking it. I'm sure it's negligible. The other issue would be the extra routing of the wiring... Guess I'll have to find some clips.

This will be my weekend project!

Anyhow, as far as less light making it to the front of the tank, I didn't really notice that myself. Mostly the shadow that's cast by the socket goes out horizontally anyhow, so no concerns about a dark spot in the tank or anything like that. Also you usually don't have anything right up to the front glass anyhow since that's your viewing pane, so I don't think it's a huge concern. Maybe try it both ways and see if you notice a difference but my guess is that you wouldn't really notice.

[GMGQ]

When I was building my stand and hood, I actually found a pre-made hood w/ the new reflectors and new Icecap MH ballasts on ebay from the states.

That hood was to be hung from the ceiling, so it wasnt applicable to my setup. But it was cheaper for me to buy that hood and take the parts from it, than buy the (2) reflectors and (2) IC250 ballasts locally.


GMGQ, where abouts did you buy the Optimal reflectors?

[TheReefGeek]

Gotcha. What are the dimensions of the reflectors?

[TheReefGeek]

Are they these?

http://www.aquariumsupplycompany.com/catalog/item/3225476/2761741.htm

[GMGQ]

Yeah those look like the ones. Mine are 12" long.

http://members.shaw.ca/reefblog/reefblog/DIY/HOOD/l_050908065602_432_1_1.jpg

Are they these?

http://www.aquariumsupplycompany.com/catalog/item/3225476/2761741.htm

[StirCrazy]

In a 48" tank with two bulbs you should mount then front to back to get the maximum light distrubution. also you should shift the base of the bulbs as far back as you can as more light is thrown forward from the bulb than back wards.

a different case would be in a tank like mine where it is only 3 feet long and two foot wide I have them mounted like you do in that case as there is only 1 foot between the tips of the bulbs.

Steve

[danny zubot]

Ok my turn. I have a 36x18" tank with only 1x 400 watt MH ver it. My current relector is only a bit larger than 1 foot squared, and my bulb is perpendicular (front to back).

The reflector I'm changing to when my canopy comes is 36" long so the bulb must face parallel. How far off of center should my bulb be to cast optimal light on the center of the tank? Also, the new reflector doesn't have one of those "V" shaped light deflectors that go above the bulb. How much do those actually effect my lighting?

[StirCrazy]

Ok my turn. I have a 36x18" tank with only 1x 400 watt MH ver it. My current relector is only a bit larger than 1 foot squared, and my bulb is perpendicular (front to back).

The reflector I'm changing to when my canopy comes is 36" long so the bulb must face parallel. How far off of center should my bulb be to cast optimal light on the center of the tank? Also, the new reflector doesn't have one of those "V" shaped light deflectors that go above the bulb. How much do those actually effect my lighting?

your not going to be able to cast optimal lighting with one bulb on a 36" tank. If you go by the rule of thumb 2X2 foot for each SE bulb, you will see that like my Garage tank, no matter how you place the bulb on the tank you are going to have areas that have much lower light intensity.

the way I would do it if I were you is on an empty tank or maybe the kitchen floor flash your light up with white paper under it and see how the lighting patteren is.. then you can shift it around to the point you are happy with it.

Steve

[GMGQ]

FYI, despite the interesting swing in the voting, I decided to change the bulbs to front/back aka Perpendicular to the front of the tank. And I lowered them 6 inches:

http://www.auphanonline.com:8080/gallery/images/uploads/1/l_060620064432_432_2_4.jpg

The tank is definitely brighter, and I think the lighting is more even now. We'll see how my corals like it.

[TheReefGeek]

Your pfo optimal perpendicular reflectors are meant to be mounted perpendicular, so that is how they should go, I assumed you would have changed them after learning that.

[GMGQ]

Yes, that's why I changed it despite the swing in votes.

But I have seen a lot of people mount them Parallel too. Heck that's why I originally had them parallel.


Your pfo optimal perpendicular reflectors are meant to be mounted perpendicular, so that is how they should go, I assumed you would have changed them after learning that.

[TheReefGeek]

Definately. I would have done the same if I bought your reflectors, because I currently use their 36" reflectors, which obviously go parallel, so I would have done the same.

So I guess everyone should double check with the manufacturer of their spider-type reflectors to make sure they are using them in the correct orientation.

[danny zubot]

Have you got a pic of your lighting and tank so I can see?

[GMGQ]

Well here's a pic without any adjustments on the camera:

http://www.auphanonline.com:8080/gallery/images/uploads/1/l_060620064432_432_4.jpg

I usually tone down the expostion to -1 or -2 for better contrast though.


Have you got a pic of your lighting and tank so I can see?

[Joe Reefer]

Here is how I have mine on a 72 bow.

http://i2.photobucket.com/albums/y4/lyohemas/12.jpg

[danny zubot]

And it doubles as a food warmer!:mrgreen: