glass tank thickness

Hi! guys good day,

just a question to make sure :) and still planning on it for january 2020.
I don't have my equipment to build a DIY tank or time so I'm planning to buy 56x20x20 with thickness 8mm or 3/8 but it's so expensive
so I choose 2pcs 28x20x20 is it ok 1/4 or 6mm is the thickness of it?

also this tank size below if I can do a thickness 1/4 or 6mm, btw all rimless

1. 56x20x20
2. 48x20x20
3. 48x18x18

thanks in advance :)

I would say that glass is way too thin personally if you're going rimless. I have a 60x24wx18h rimless marine tank and that's built out of 15mm!

I do have a 60x18x18 made out of 6mm, but it is very heavily braced and has a thicker base.

You can search a glass thickness calculator online.
I researched it years ago and I'm pretty sure that once you go over 18" you need 8mm minimum, at 24" it's 10mm minimum and of course the span or total length factors into the bow factor, so that effects thickness requirements as well...
6mm for option 3 will work but you will have to standard brace or euro brace the top of the tank...

thanks kev1310 and danotaylor for the info,

I want to try safer 8mm on this tank 56x20x20 or also 6mm with very heavily braced and has a thicker base like kev1310 said.
I will buy 1st week on january hope they have discount since it's new year :)

Thicker is better, always. Have you thought about where the water and critters would go if it lets loose? The cost of this can far exceed the cost of thicker glass. The bracing it would require would make this an unsightly tank. If it's just a breeder in the basement, fine, but a show tank in the living room????? There's an old saying my grandfather taught me very young, BUY ONCE, CRY ONCE. I didn't understand the meaning then but I sure do now. I know waiting and saving isn't easy. Took me 4 years to setup my 220. But when I look at it the last thing I think about is the cost. Probably because I don't like or use CC, lol!!!! Good luck brother.
Later
NCH