Glass Aquarium Bow

[piranhaman00]

Hello,

I have a 48x35” aquarium with aluminum trim that has one center brace between the 48” sides, made by custom aquariums in Neenah Wi, I have reached out to them and waiting response.

I noticed yesterday that the 35” panel has a slight bow to it, it’s about 2.5mm but it was difficult to measure with a level so I will verify with straight edge tonight.

It’s strange because the 48” sides have no bow at all, anyone else with glass tanks that have bow? Is this normal to have?

 

[HighlandReef]

To the best of my knowledge, glass shouldn’t bow. In general, glass bowing like that = no good. I would be concerned about it developing a leak or even worse, a blow out.
When I rebooted my 210, I check my tank for any signs of bowing and it has none.
It’s probably safe to say that if a 6’ tank has no bowing, a 4’ tank shouldn’t have any either.
Hopefully manu can provide some guidance and warranty as needed.

 

[piranhaman00]

To the best of my knowledge, glass shouldn’t bow. In general, glass bowing like that = no good. I would be concerned about it developing a leak or even worse, a blow out.
When I rebooted my 210, I check my tank for any signs of bowing and it has none.
It’s probably safe to say that if a 6’ tank has no bowing, a 4’ tank shouldn’t have any either.
Hopefully manu can provide some guidance and warranty as needed.

An internet search provides many instances of glass bowing. All of the aqueon petco aquariums bow, when I reached out to them regarding a 29 gallon, they said that their tolerance is 1/2 the glass thickness. With my aquarium being 3/8” following that guideline would allow 4.5mm.

I found instances of people have tanks running with 10mm glass with a 10mm bow for years!

I asked here to see if anyone else has noticed this after tank running for some time. Not sure if it was there from the start but assuming so

 

[HighlandReef]

Interesting, my 210 is an aqueon. 1/2” glass sides.
I’ll have to check again when I get home.
I took a 6’ level to the top and bottom edges, next to the plastic bracing and didn’t see any noticeable bowing but I didn’t check towards the middle of glass pane.
Anyway, glad it worked out.

 

[Sean Clark]

Custom Aquariums often uses different glass thickness on different sides of the Aquarium. It wouldn't supeise me if the 35" sides are thinner than the 48" sides.

 

[piranhaman00]

Custom Aquariums often uses different glass thickness on different sides of the Aquarium. It wouldn't supeise me if the 35" sides are thinner than the 48" sides.

I paid for 3/8” on all sides at least

 

[vetteguy53081]

Hello,

I have a 48x35” aquarium with aluminum trim that has one center brace between the 48” sides, made by custom aquariums in Neenah Wi, I have reached out to them and waiting response.

I noticed yesterday that the 35” panel has a slight bow to it, it’s about 2.5mm but it was difficult to measure with a level so I will verify with straight edge tonight.

It’s strange because the 48” sides have no bow at all, anyone else with glass tanks that have bow? Is this normal to have?

Not good and unusual but I would suggest reducing 50% of water into containers and attaching Euorobracing to the tank to assure further stress on the geometry of tank

 

[Soren]

I paid for 3/8” on all sides at least

Can you confirm the glass thickness is consistent on all sides? It seems odd to me that the shorter side would bow more than the longer side if all other variables including glass thickness are consistent...

...although the center brace might be making the difference, depending on how the glass is bowing.

 

[piranhaman00]

Not good and unusual but I would suggest reducing 50% of water into containers and attaching Euorobracing to the tank to assure further stress on the geometry of tank

The manufacturer said it’s pretty common for glass tanks to bow and said my pictures are not out of the ordinary.

Can you confirm the glass thickness is consistent on all sides? It seems odd to me that the shorter side would bow more than the longer side if all other variables including glass thickness are consistent...

...although the center brace might be making the difference, depending on how the glass is bowing.

I can’t because the side panels are on the inside of the panels.

Ya it must be the center brace, but tanks that are 48”+ wide don’t have braces going both directions.

 

[vetteguy53081]

The manufacturer said it’s pretty common for glass tanks to bow and said my pictures are not out of the ordinary.


I can’t because the side panels are on the inside of the panels.

Ya it must be the center brace, but tanks that are 48”+ wide don’t have braces going both directions.

Shame on them. I was an LFS and never seen or heard this. Acrylic will bow BUT very minimally

 

[piranhaman00]

Shame on them. I was an LFS and never seen or heard this. Acrylic will bow BUT very minimally

Simple google search reveals many cases. The petco aqueon tanks bow considerably. This is how I first noticed it and then checked this CA tank. The 29 bows more with thinner glass and is in tolerance per the Manuf

 

[Soren]

The manufacturer said it’s pretty common for glass tanks to bow and said my pictures are not out of the ordinary.


I can’t because the side panels are on the inside of the panels.

Ya it must be the center brace, but tanks that are 48”+ wide don’t have braces going both directions.

Glass will always bow under one-sided loading as is the case in an aquarium, but how much it bows and how much bowing is allowable depend on several factors. I don't have enough experience to be able to answer how much concern you should have in your case...
Is there aluminum on all corners and rims of your aquarium that would prevent measuring glass thickness on the short sides? Also, is the measured bowing just a curve from front to back, or a bulge from top to bottom as well?
Do you know if your tank is made of tempered glass or not? Tempered glass can allow more bowing before it is at risk of breaking than regular plate/float glass. I would tend to trust the manufacturer, since they have their name at stake for failure due to improper design, but I also understand that you assume some of the risk since your livestock and house will be damaged if the tank fails.

Hopefully others with more experience can give input as well. Joe at Glass Cages may have good advice for you: @Joe Glass Cages

 

[piranhaman00]

Glass will always bow under one-sided loading as is the case in an aquarium, but how much it bows and how much bowing is allowable depend on several factors. I don't have enough experience to be able to answer how much concern you should have in your case...
Is there aluminum on all corners and rims of your aquarium that would prevent measuring glass thickness on the short sides? Also, is the measured bowing just a curve from front to back, or a bulge from top to bottom as well?
Do you know if your tank is made of tempered glass or not? Tempered glass can allow more bowing before it is at risk of breaking than regular plate/float glass. I would tend to trust the manufacturer, since they have their name at stake for failure due to improper design, but I also understand that you assume some of the risk since your livestock and house will be damaged if the tank fails.

Hopefully others with more experience can give input as well. Joe at Glass Cages may have good advice for you: @Joe Glass Cages

Ya the trim is all around so there is no way to measure the glass , it’s not tempered, normal glass. The bow is measure by putting a straight edge on one side and measuring the gap at the other. It’s most noticble on the top but the bow is on the whole panel.

 

[nereefpat]

Glass under load will deflect, as all things do. I don't have experience as to what is normal. 2.5 millimeters over 3 feet isn't very much. I'm surprised you noticed it. I'll have to check my tank when I get home.

I was going to ask exactly how you are measuring, but I see your new post. Interesting. I'm curious as to what tank builders and other long-time big tank keepers would say.

 

[Soren]

Ya the trim is all around so there is no way to measure the glass , it’s not tempered, normal glass. The bow is measure by putting a straight edge on one side and measuring the gap at the other. It’s most noticble on the top but the bow is on the whole panel.

Since the bow is more noticeable at the top, it seems to imply that the support from the trim is not enough to limit the bowing as well as the center brace on the 48" side. I don't know that you would need to do this, but a Euro-brace would help limit the bow (although it seems strange to me that the top trim does not already eliminate measureable bowing? ...full trim should act similarly for bracing).

I don't know enough to give you answers, so hopefully others with more experience can help with solutions or alleviate your concerns.

 

[Joe Glass Cages]

Glass will always bow under one-sided loading as is the case in an aquarium, but how much it bows and how much bowing is allowable depend on several factors. I don't have enough experience to be able to answer how much concern you should have in your case...
Is there aluminum on all corners and rims of your aquarium that would prevent measuring glass thickness on the short sides? Also, is the measured bowing just a curve from front to back, or a bulge from top to bottom as well?
Do you know if your tank is made of tempered glass or not? Tempered glass can allow more bowing before it is at risk of breaking than regular plate/float glass. I would tend to trust the manufacturer, since they have their name at stake for failure due to improper design, but I also understand that you assume some of the risk since your livestock and house will be damaged if the tank fails.

Hopefully others with more experience can give input as well. Joe at Glass Cages may have good advice for you: @Joe Glass Cages

Thanks for looping me in @Soren

This is a tough one. I can only speak for our engineering and builds.

I would default to this manufacture exclusively for their input.

 

[manytanks]

It doesn't hurt to put a brace on. Isn't the most appealing visually. But it'll put your mind at rest.. I myself am struggling with a 56"L x 46"H piece of tempered glass. 3/4" filled 200g's or 3/4's and it's deflecting 1mm. It's braced but 4' is a long stretch.. nervous... any thoughts?