Glass too thin for tank?

Jbakewell

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Hi everyone

I’ve just bought a 60x30x30 tank with 4mm glass panes. While I think the manufacturer is trustworthy, I’ve been a bit concerned as to whether the glass might be too thin for the tank size.

Also, my filter is a canister filter that hangs on the side on the tank (see image). I’m going to put a thick sponge underneath it to take weight off the braces, but I’m not sure it will be safe given the glass width when everything is up and running.

Thoughts? Has anyone here used a 4mm glass tank before of a similar size?

Thanks!
 

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alto

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ADA uses 6mm glass, as does UNS for their 60U (60 x 36 x 36cm)

4mm rimless - be very careful that it’s level in all directions, that you’ve used a suitable anti-vibration mat (similar to ADA Garden Mat), and never accidentally knock it ... and inspect the silicone seals closely :wideyed:

What’s the Manufacturer warranty?
 

zozo

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4mm is a standard thickness for this size, for example, the Hagen / Marina Solid glass tanks 54 Litre sold in many pet stores. Pretty common around Europe. Fluval is actually also from Hagen Group.

I've used it for many years and never had a structural problem with it. And the tank still stands in the garden today.
 

lazybones51

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zozo

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I have seen that 5mm optiwhite tank in AG and there's a slight bow in the front, which you don't get in a 6mm ADA. I imagine 4mm is going to bow a fair amount over 600mm.

Yes, it does about 10 to 20mm total in the centre. But that's no structural problem. I also went 6mm on a 90x35 cm tank and this bows similarly.

And once went for 125cm x 20 cm with 4mm glass and the centre bow was over 30mm over a length at 125cm it looks awful but still not a structural problem.

Glass is pretty flexible under equal pressure, what it doesn't like is point pressure and contortion.

See this: In aquarium building, a safety factor is used related to glass thickness pressure resistance.

Commonly SF 2.5 is considered safe.
sf2.5.JPG

SF4 is Very Safe.
sf4.JPG

SF8 is equaly very safe.
sf8.JPG


If for your peace of mind SF8 is very safer than go 6mm :)

http://theaquatools.com/building-your-aquarium/
 

Jbakewell

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4mm is a standard thickness for this size, for example, the Hagen / Marina Solid glass tanks 54 Litre sold in many pet stores. Pretty common around Europe. Fluval is actually also from Hagen Group.

I've used it for many years and never had a structural problem with it. And the tank still stands in the garden today.

This is reassuring. I guess it wouldn’t be standard if even a minority of people with these tanks reported problems
 

Jbakewell

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Yes, it does about 10 to 20mm total in the centre. But that's no structural problem. I also went 6mm on a 90x35 cm tank and this bows similarly.

And once went for 125cm x 20 cm with 4mm glass and the centre bow was over 30mm over a length at 125cm it looks awful but still not a structural problem.

Glass is pretty flexible under equal pressure, what it doesn't like is point pressure and contortion.

See this: In aquarium building, a safety factor is used related to glass thickness pressure resistance.

Commonly SF 2.5 is considered safe.
View attachment 128537
SF4 is Very Safe.
View attachment 128538
SF8 is equaly very safe.
View attachment 128539

If for your peace of mind SF8 is very safer than go 6mm :)

http://theaquatools.com/building-your-aquarium/

If these calculations are valid it looks like It will be ok? I was concerned 4mm would be on the very edge of safe, but if it is indeed considered ‘very safe’ than returning it for 6mm would be overkill no?

Would be a bit frustrated if it bows a lot though. It’s an optiwhite tank and I’d hate for the view to become distorted
 

zozo

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If these calculations are valid it looks like It will be ok? I was concerned 4mm would be on the very edge of safe, but if it is indeed considered ‘very safe’ than returning it for 6mm would be overkill no?

Would be a bit frustrated if it bows a lot though. It’s an optiwhite tank and I’d hate for the view to become distorted

For the safety, it ain't an issue the rest is personal aesthetical value and choice. :) I'm also not sure if 6mm will not bow at all. Visually it still might look straight, but once you place a perfect flat ruler over the glass you still might see a little bow. That's for an owner of such a tank to try and confirm or deny. My gut says it still bulges a little.

From experience, i know that even a 25mm Euro brace on a bowing tank and it didn't prevent it from bulging out. And a euro brace is a 25mm wide additional strip sealed perpendicular to the top of the front and back panel entire length. It reduced bowing for 75% but it still bows a little.

Also does the bowing depend on the quality of the seals?

No not at all, the bowing is in the flexibility of the glass panel related to its height. Since the pressure of the water relates to water column height, this means 30cm water gives more outward pressure than 20cm water. This you can see to take 10cm water out of your 30cm tank and see it bow less.

Like the example bellow shows, if the tank gets taller the glass needs to be thicker.
tall.JPG
 
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Jbakewell

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For the safety, it ain't an issue the rest is personal aesthetical value and choice. :) I'm also not sure if 6mm will not bow at all. Visually it still might look straight, but once you place a perfect flat ruler over the glass you still might see a little bow. That's for an owner of such a tank to try and confirm or deny. My gut says it still bulges a little.

From experience, i know that even a 25mm Euro brace on a bowing tank and it didn't prevent it from bulging out. And a euro brace is a 25mm wide additional strip sealed perpendicular to the top of the front and back panel entire length. It reduced bowing for 75% but it still bows a little.



No not at all, the bowing is in the flexibility of the glass panel related to its height. Since the pressure of the water relates to water column height, this means 30cm water gives more outward pressure than 20cm water. This you can see to take 10cm water out of your 30cm tank and see it bow less.

Like the example bellow shows, if the tank gets taller the glass needs to be thicker.
View attachment 128556

I think I’ll see how it fares for a couple of months, and if it ends up bowing like crazy I’ll add a centre brace in the new year. Thanks for the advice
 

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