Building my own tank – What size glass or Acrylic should I use?


New member
Building my own tank ââ"šÂ¬Ã¢â‚¬Å“ What size glass or Acrylic should I use?

I am looking to build my own tank and didnââ"šÂ¬Ã¢"žÂ¢t know what to use, glass or Acrylic?
The dimensions areââ"šÂ¬Ã‚¦

Tank Length = 72 inches
Tank Width = 18 inches
Tank Height = 19 inches ââ"šÂ¬Ã¢â‚¬Å“ Height would be 20 with an inch for the overflow

Tank Volume = 106.6 Gallons

Is there a formula that would tell what thickness would be needed for this?



New member
There's a calculator on the Cyro website to determine the thickness of cast acrylic you'd need to use. But, this is a VERY conservative calculator, when I punch your numbers in it says you need 3/4" (actually .70") I believe most builders would use 1/2" cast acrylic and a nice sturdy top brace all the way around. For glass you'd use 3/8" I think, but that's a guess. I built a sump somewhat with these dimensions; a little shorter, a little wider, around 100 gallons. I used 3/8" cast, but remember this had some dividers gong across the tank, which really stiffens it up.

If it were me, I'd have a go with 1/2" (or 5/8" if you want to really play it safe) cast acrylic, only cyro GP or spartech polycast, and use MC bond as the welding solvent, as I have a feeling it does slightly better joints than weldon #4, and acts a little more slowly, giving you time to pull the pins on that big bottom joint. Not a good first acrylic project!


Premium Member
Glass would need to be thicker than acrylic. Mostly because since your gluing glass with silicone the thicker the glass the more glue surface on the but joint. The bigger the tank the bigger the glue surface needs to be so that the seams don't fail. Most people who make their own tanks don't use plastic, wood, or angle iron frames so the only thing holding is the glue joint.

Besides more comparible strength, acrylic can be smaller because the corners are either welded or bent. However acrylic is less ridgid and bows so it need adequate bracing.

Glass is cheaper that acrylic until the thickness goes above 1/2" then acrylic becomes more price competitive.



New member
I don't know that I would trust that garf calculator. It never recommends more than 1/2" acrylic (even for a 500g tank).