# 125G glass bowing question



## Neogenesis (Jan 4, 2008)

Hey guys,

I picked up a used 125G tank, which seems to be built from the factory without a center brace. I am noticing some bowing in the glass and want to know if that's normal for a glass tank. The only reason I noticed is it's got a glass center section that "snapped" into place when the tank was empty, not it just sits in there.

Is this normal or something I should be concerned about? It never even crossed my mind that it could be a problem when I purchased it.

Thanks!!

Scott


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## TKC747 (Dec 5, 2008)

I don't know if its normal or not but not all aquarium brands are built the same. I've noticed that for a 55 gallon, Aqueon/All-Glass produces a tank that is noticeably thicker than other brands. I'm not sure that a 125 gallon tank would be used for reptiles but I think the ones which house reptiles use thinner glass. Ask the former owner whether he had fish in it rather than using it to house a huge python or something...I hope this gives you a clue until someone with experience responds to let you know for sure.


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## Neogenesis (Jan 4, 2008)

I would highly doubt this is a reptile aquarium. The glass is a lot thicker than my 75 and it's a heavy SOB. I do know the former owner kept fish in it, I'm just a little concerned if this was normal or not. I'll have to measure it and see exactly how much it is bowing. I would hate to see the tank shatter and drop all that water into my living room.

Scott

added a pic showing the drop in center glass section


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## TKC747 (Dec 5, 2008)

no doubt,

Sorry I wasn't more helpful


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## Neogenesis (Jan 4, 2008)

np....any responses are appreciated

Scott


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## bfg112 (Feb 13, 2009)

From the picture, that looks like the original factory trim around the top. If there is nowhere on the top trim that looks like a brace was cut out I would guess the tank wasn't built with any. To answer your question, yes it is normal for the glass to bow a little. So, if the tank wasn't built with braces I would not worry about the bow. If it looks like braces were cut out, you might want to consider rigging up some braces.


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## TKC747 (Dec 5, 2008)

check these out: I found these using the search option

http://www.cichlid-forum.com/phpBB/viewtopic.php?t=169314&highlight=bowing

http://www.cichlid-forum.com/phpBB/viewtopic.php?t=191852&highlight=bowing


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## Deeda (Oct 12, 2012)

Can you show a closeup of where the middle glass 'drops' in?


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## Neogenesis (Jan 4, 2008)

Definitely will, but will have to be after I get off work. It looks like a normal tank, just no center bracing.

Scott


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## TKC747 (Dec 5, 2008)

check out what it should be:

http://saltaquarium.about.com/od/pl...bles--Diagrams/Glass-Thickness-Calculator.htm


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## Neogenesis (Jan 4, 2008)

Thanks for that link....I didn't know that existed.

Here is the pic that was asked for.

I did a little measuring tonight, here is what I'm seeing.

Tank is built from 1/2 glass. It is bowing in the middle around 3/8 of a inch. So I need to reference that graph in the link above and see if that's acceptable.

Scott

Please ignore my ghetto lighting, a better setup will be on the way soon.


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## Neogenesis (Jan 4, 2008)

So....if I read that table correctly and figured that right, it says that I'm a bit over it's recommended sizes.

Anyone care to double check my work?

And the bow still makes me nervous.

Scott


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## Deeda (Oct 12, 2012)

Thanks for the pic. I don't have an answer for you but it seems that a 3/8" bow at the middle *may* be a problem. You don't happen to know who made the tank, do you? The reason I ask is because I acquired a 75G glass tank that has the same glass lid configuration that you do. The tank was made by O'dell (now out of business). I haven't set it up yet as it needs to be resealed.

You may want to wait for additional answers from others here. You could always add a permanent glass center support with silicone but that would entail draining the tank, cleaning & drying the surfaces before attaching the new support, and using clamps to hold it in position for 72 hrs til silicone cures. Just a thought and may not be necessary.

Sorry I couldn't be more help.


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## TKC747 (Dec 5, 2008)

I calculate that 1/2 inch thickness is 12.7 mm, which is 3.7 mm thicker than 9mm with a safety factor of 4.61, whatever that means ... sorrry to say I don't know what a safety factor is, which is not really specified on this chart...sorry to get your hopes up with this half usefull chart. *The bowing would make me nervous too and distrust the chart*. Here's an idea for you, look up various aquarium manufacturers who produce your size tank (125 Long)= 6ft x 18 inch x 20 inch, *and ask them what the price is and how thick the glass is *and you should have a better sense of safety with or without bowing. The better makers, which cost more money will make better products but hopefully someone with experience will chime in.

Best of luck until tomorrow, I will follow this thread to see what you find (I would do the work myself but not possible at the current moment, I will help if you like, PM me and we can investigate this over the following week...I would drain the tank meanwhile if it bows without knowing how acceptable it is!)


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## noddy (Nov 20, 2006)

To be quite honest, I wouldn't put water in that tank. I have a 6' tank that is made of 1/2" glass and it is braced every two feet. I would accept nothing less than zero bowing.


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## Neogenesis (Jan 4, 2008)

Ok.....I'm sorry, I mis measured a bit, I hate doing things when I'm tired, I make mistakes like this. The tank is bowing 3/16ths, not 3/8ths. I've also snapped the pics as were requested. So, given that information, thoughts?

Scott


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## Deeda (Oct 12, 2012)

Well now, 3/16" sounds so much better than 3/8" bow. I've been discussing this with my mechanically inclined better half. Looking at your latest pics, it appears that the top plastic brace is not cracked or separated, which is a good thing. I am also assuming the trim is firmly attached to the top.

What we would do in this situation, is measure front to back on the two ends & the middle when the tank is full of water. Then drain the tank halfway & take the same measurements again. If it is still 3/16", drain further to compare if there is a difference. If it is the same, don't even worry about it as it was probably built that way, unless someone else took it apart previously.

I don't know if 3/16" is an acceptable deviation. We would probably add a center glass brace at the top, siliconed to the front & back glass, as a precaution. It would probably need to be 1/2" thick & 3" wide to be sturdy enough.


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## Neogenesis (Jan 4, 2008)

You are right about one thing, this is one heavy tank. I just got back from the fish store and 125G tanks there look to be thinner than 1/2", didn't measure cause I forgot my tape measure. It was definitely thinner though. After moving in my sisters new 180G tank, weight of my 125g isn't far off from hers, both are made from 1/2" glass.

I think I will pump the tank half empty, as I have enough tupperware bins to store the water, so storage and reuse of it won't be a problem. I think I'll do that and report back. I do know there is a difference, as there is a glass center section that sits in there, but when the tank was empty, it snapped in. Now it just sits in. I'll pump out as much water as I can and take measurements along the way.

Thanks for the reply's,

Scott


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## Neogenesis (Jan 4, 2008)

Well.....At 5 1/2" below the bottom of the frame, the bowing is gone. So it's only when the top 1/3 or so is filled that the bowing begins.

Scott


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## Deeda (Oct 12, 2012)

I would probably add the glass brace. I just checked my 220G tank with 1/2" glass & it only deflects 1/16" when full, (tank is 72"L x 24"W x 30"D). But it does have the factory trim with 2 center braces. Sunday is water change day, so I'll check it 1/2 empty then.


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## Neogenesis (Jan 4, 2008)

I think I'll add one just for saftey sake, but I don't think it's needed anymore. I admittedly cross posted this on multiple sites to hopefully reach a large group of people. I've been getting a lot of feedback on one of the salt sites.....they seem to think it's ok. It's a older tank and this is the way they were built back then. So....I'm feeling better for the time being until I get a brace added.

Here is a pic after I refilled and added all the rock I have. I think it's time to get some more. Hard to believe there are over 30 fish in there huh? They all hide when it's photo time.

Scott


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## stangmus (May 14, 2008)

I have tank exactly like that. I purchased it used in 1989. It has bowed since the day I brought it home. It has been through 4 moves, and it has never given me a problem. That tank was probably manufactured in the early 80's. I wouldnt worry about it.


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## Neogenesis (Jan 4, 2008)

Stangmus,

Thanks for the reply. I've gotten a few responses now that have stated just that. I'm feeling a lot safer than I was with this tank 2 days ago.

Scott


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