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Discussion Starter · #1 ·
I have a 46 gallon All Glass bow front I will be setting up soon. I am wondering what the effects of hot halides will be on that middle plastic bar. I plan on getting a 36" hood with dual halides and want to make sure I get something that wont melt/degredate the bar in the middle of the tank.

Do any of you who have 46 bows have suggestions for light hoods or pendants and the height above the bar I should keep the hood/pendants in order to retain the integrity of the bar?

Also, I am looking at the oceanic tank at my LFS- it is $300 and I could trade in my current tank. It seems to have thicker glass and a thicker bar- any thoughts?

Thanks much
andrew
 

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I own a 46 bow front and i just recently put a new light on i was going to go with MH but it measured 15 inches and on the front would stick over 2 inches so i went with a 156 w HO T5 fixture tanks only 18 inch deep anyway no need for MH in my opinion and as far as that middle bar i took it out of mine blocked out one of my blue moon leds.
 

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Dual halides won't be over the center brace, you should be safe. If you are really concerned about it, you can place a piece of colored acrylic over it to protect from heat and uv.
 

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as far as that middle bar i took it out of mine blocked out one of my blue moon leds.
The center brace is not optional, it is required for the integrity of the tank. You have a disaster in the making.
 

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The center brace is not optional, it is required for the integrity of the tank. You have a disaster in the making.
Yep it won't be IF but when .... Consider getting the tank eurobraced if you don't want the center bar but by all means either put it back or eurobrace it

I had two friends who had their acrylic tanks crack on upper brace due to MH getting too hot... Yours is glass but from above it looks like brace is plastic so I would think susceptible to cracking and yellowing
 

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Discussion Starter · #6 ·
yeah i definitely have ZERO plans on removing it!!! I know it is an integral part of the tank itself. That's why I want to make sure I get a hood that is friendly to that piece. I was wondering if I could enhance the security of it by adding something over it. Acrylic or something similar is a great idea- just another layer of protection. I like to be better safe than sorry :) Mattrich- might wanna see what you can do about replacing that brace- it helps keep that front piece of glass from popping off, from what I understand!
 

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did some research and yeah it is needed but mine didnt have much preasure on it so i'm going to get a rubber ended bar clamp barely apply preasure and silicone a 1/4 inch piece of plex in the same place
 

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As someone who has a 36" tank, finding a dual MH fixture for that length is difficult. For some reason many manufacturers only have make single MH for 36" (like the Current fixture of my 40 breeder. But my 65g has the center brace too and as a result I had to go with two independent pendents. However, Aquatic Life has a nice dual 36 fixture: http://www.marinedepot.com/AquaticL...iums-AquaticLife-AK01205-FILTFIMHTSHI-vi.html

It is slightly more expensive but then again you are getting two 150w MH, T5, and it has its own controller.
 

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As someone who used to build outdoor pools, bracing is all about keeping the correct pressure at the right place. That plastic bar keeps the rim from bowing out just slightly thus keeping pressure off of the seams. Glass, unlike some acrylic, does not "bend" well to pressure and will shatter... some acrylic tanks have noticeable bows in the sheet where if it was not braced... but then again acrylic is chemically welded while glass is not. The bar may seem "flimsy" but it is how you are looking at. It is not meant to be "solid" and that is why if you touch it it kinda bends and jiggles... but try and stretch that plastic longwise like the tank would do, it stands up to a lot of force.

Take my two tanks for example, the 40B which is braceless is 3/16 inch glass, the 65g is 5/16 with a center brace. The higher the tank, the more the water pushes at the top center of the glass panes. I have seen large (above ground) pools fail and they always fail from the rim.
 

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Discussion Starter · #12 ·
Thanks Doc- That kind of answers a question I was going to ask, but will ask anyway... I have the All Glass 46 gallon tank. My LFS has- I think it is an Oceanic- for $300. The center brace feels a little stronger and the glass I think is a little thicker. I was wondering if I should trade up and get the more expensive tank if it is built stronger, but maybe it doesnt matter? I assume the All Glass should work fine and not fail... Doesnt anyone know the difference between thos etwo- or does it even matter which brand you buy?

As for the hood, yeah, I am having a tough time trying to find one. The one you mentioned was recommended by marine Depot to me but a member of this site steered me clear of it because of the type of halide bulbs it uses. Any thoughts on that? I may go with pendants (like the ones you recommended to me) but I really want to do the dawn/dusk/moon lighting thing that hoods offer. Is that possible to achieve with a pendant system (without ending up with a mess of different lights and fixtures)?
 

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did some research and yeah it is needed but mine didnt have much preasure on it so i'm going to get a rubber ended bar clamp barely apply preasure and silicone a 1/4 inch piece of plex in the same place
Silicone will not work. It will not stand up to the outward pressure that will be placed on it. It needs to be bolted into place with nylon bolts/nuts. If you don't have enough room to correctly attach the brace, you can buy a replacement top frame.

As I said, it is not optional and must be strong enough to withstand the outward pressure.
 

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I think All-glass bough out Oceanic a few years ago... They kept their names but the old Oceanic tanks were overbuilt like tanks. Now, I thin they are identical for the most part.

The G12 halides are "unique" but no where near as rare as the used to be. I would say you will not have a problem finding replacement bulbs now or in the future. Ushio makes the G12 bulb and they are a steady company without a lot of changes to their brand. Aquatic Life also has their "brand" of bulbs but I have it on good authority that their brand is actually made by Ushio as well. There is little difference between the two other than price ($65 for AL, $100 for Ushio). Ushio might be a bet more consistent for color but I have not seen any difference reported.

It is tough having a lot of flexibility (color, light schedules, etc) with pendents without a lot of lights. It is the one big downside as it is more of a single use approach.
 

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The higher the tank, the more the water pushes at the top center of the glass panes. I have seen large (above ground) pools fail and they always fail from the rim.
Warning: Nitpick.
Actually the pressure of any liquid medium is proportional to depth P=pgh (P=pressure, p=density of fluid, g=grav accel, h=depth from free surface). So the pressure due to the water at the top of the tank = 0. Most of the pressure exerted on the walls of the tank comes from the bottom half.

For example: Pressures at various heights on my 46 bow.

Top: (1.025 SG)(997 kg/meter^3)(9.81 meter/s^2)(0 inches)(meter/39.37 inches) = 0 Pascals = 0PSI. --sorry, I hate working in the USC system--

@5": P=0.184 PSI
@10": P=0.369 PSI
@15": P=0.554 PSI
@20": P=0.729 PSI (bottom)

Force = (Pressure)(Area)

Fbottom~(0.729PSI)(36*(12.5+16)/2)avg.area=374 lbs! It seems to me that the bottom brace is MUCH more important than the top. I'm not a glass man but I do know that elastic modulus of glass is high and therefore will not deform too much before breakage. Force causes deformations so it is my educated guess that the top brace is mearly an insurance policy against deformation in aquariums that i) are deep, or ii) have large surface areas; and not so much to strengthen the seams...maybe the bottom brace helps with strength.
 
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