# buldging tanks?



## qwerty (Dec 15, 2009)

I've got 2 aquariums purchased from Big Al's.

I noticed this morning that the front (and I assume the back as well) panes of glass are bowing a little bit. 

It's not really noticeable to the eye, but it's definitely not flat when tested with a straight edge... Also noticeable when measuring the width of the aquarium from the middle and the sides. But my friend's larger tank can be confirmed as flat...

Should I be worried? Cause after having some pretty awful experiences at Big Al's, I kinda am...


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## KnaveTO (May 13, 2007)

Some tanks will bow at the middle. Depending on the length of the tank they will often have centre braces to hel peinforce the glass. How long is your tank and what is the degree of the variance between the join and the middle where the bow is most pronounced? I used to have a 4' long 90 gallon tank years ago that had a centre brace as well as a 2 or 3 mm bow at the mid point on the length as was perfectly fine.


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## qwerty (Dec 15, 2009)

it's a 30 inch long tank with about 3mm bow.

The other is 20 inches long with I'd say 4mm bow.

These definitely aren't 4 foot tanks... lol


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## CanadaPleco (Sep 7, 2009)

Holly cow my 10 foot tank doesnt bow that much.


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## Jiblets (Dec 24, 2009)

Is that a 4mm bow on each side? Or really 2mm adding up to 4mm wider?

If it's 2mm that's normal. The 20" glass is pretty thin.

Tank bowing is normal - It's also why when you install the sliding glass tops, they tell you to fill the tank, BEFORE cutting the plastic railing. Sometimes it pays to read the instructions first...


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## qwerty (Dec 15, 2009)

The way I'm measuring is by aligning a meter stick with the corners of the tank, then measuring the amount of plastic trim sticking out in the middle.

So yes... 3mm and 4mm on just the front pane... Not the front and back pane added together...

I get the same measurements holding the meter stick as flush against one side of the aquarium as I can and then measuring the gap between the tank and the meter stick on the other corner...


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## Jiblets (Dec 24, 2009)

The 20g (24") I have only bows 2mm. How high is your tank? Mine's only 13". If it's a tall tank, the bow will be larger as it's holding back more weight. My old 33g 36" probably bowed 5mm, so I wouldn't worry about it.

Interesting it bows that much...


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## qwerty (Dec 15, 2009)

The one with the 3mm bulge is 18 inches high, 30 inches long...

The one with the 4mm bulge 12 high and 20 long.


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## solarz (Aug 31, 2010)

I just noticed that my 20-gallons from BA's is having this problem as well. I'm not sure exactly how much the bulge is, but it's definitely noticeable because the trim does not "hug" the light hood anymore.

Qwerty, what happened to your tank in the end? Did you replace it or left it alone?


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## BillD (Jun 5, 2006)

Bowing in an unbraced tank is normal. Pretty much every tank up to 36" is Unbraced and they all bow.


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## J-P (Feb 27, 2011)

I'll have to check my 6' tank after reading this... I have no brace either...


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## Riceburner (Mar 14, 2008)

my 4' tall one bows a couple of mm when full and once the first few inches of water are removed during the WC, it "straightens". Has done this for years. No brace.


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## splur (May 11, 2011)

One of my 35 gals is bowing like 3 mm. Surprisingly my 50 gallon isn't at all, oh thick glassed aquariums.


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## adrenaline (Jan 17, 2011)

hmm... I just picked up a 5 foot 110 Gallon... It does not have any centre brace either... 1/2" glass though. 

I did a leak test in my garage, held up no leaks luckily, but i'm still going to reseal it. however i had a bulge in the middle. I belive it was somewhere in the range of 3-5 mm, but that's measuring front to back, so at most maybe 2.5 mm per side. 

Anyone have larger tanks that could help out here? Do you think it would be wise for me to go to a glass shop, and have them cut some braces for me to install? I'm literally in the process of resealing it now, so now would be the time...

the top trim is not joined either, came off in 4 peices... dimemsions are 61" x 20" x 21"


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## BillD (Jun 5, 2006)

If you want a centre brace to make it easier to add glass lids,or to keep the front and back straight to make it easier to add a canopy, by all means add it now. The tank does not otherwise need a brace.


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## adrenaline (Jan 17, 2011)

that's great news! I'll probabl end up adding one just to make addig lids easier. But i'm glad it's not structurally relevant. 

The only other issur i have is the bottom trim. one of the shortter sidep epeices was msing when i got he tank. I was trying to figure out where to et a new peice, or if I should make one, or just drop the tank into a recesed cavity in a tand (will be building one once the resealing is done so it has tim to cure)


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## BillD (Jun 5, 2006)

Lots of stores carry the trim. I would check with NAFB. The trim isn't necessary so you could remove the rest of the bottom trim, and set it on a piece of styro.


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## adrenaline (Jan 17, 2011)

what's the purpose of the styro? i've seen lots of people using it below their tanks. all my other tanks are on Store bought wooden stands (big als) or metal stands without styro.

The 110 will be on a custom wooden stand i'm making, so it would be very easy to incorporate it. I figure since i'm doing a solid bottom (plywood) it would be good insulation for tha tank. But what else does it do? and any specific stryo you would recommend?


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## BillD (Jun 5, 2006)

Styro will absorb minor discrepencies in flatness on your stand top, which is especially important if you have a tank with not trim. A grain of gravel beneath a trimless tank on solid topped stand will fracture the bottom pane. A trimless tank sitting on styro has a stronger bottom than one suspended.


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## adrenaline (Jan 17, 2011)

so glad you mentioned this before I finished the stand... every other tank i have has trim, so I would've never come across this. Styro it is!

Assuming any old variety will do? Or are there types i should avoid? I figured I can pick it up from Home Depot.


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## BillD (Jun 5, 2006)

I use the white styro, which is available in 24" wide sheets at HD, 3/4" thick.


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## adrenaline (Jan 17, 2011)

awesome! i'll pick some up! Thanks again for all the help!


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