Well... lost my 60 gal cube tonight

[sternicus]

Thinner the glass easier to crack or break under pressure from bulkhead over tightening or pressure of water itself.
Although a 1/2" glass will also break under pressure due to over tightening but changes are less. Over tightening may cause stress and water pressure over time might crack a 1/2" glass as well. So all glass can break but thicker it is lesser the chance.
Best way to tighten a bulkhead is to place the gasket on the water side and fling/nut on the outside. Hand tighten to your best then use a tool to push it just a hair more.

Interesting. On this occasion, the glass was 1/4” so I think that’s the main issue. But also I don’t think a bulkhead could crack glass unless it’s crazy tightened

 

[sternicus]

Thinner the glass easier to crack or break under pressure from bulkhead over tightening or pressure of water itself.
Although a 1/2" glass will also break under pressure due to over tightening but changes are less. Over tightening may cause stress and water pressure over time might crack a 1/2" glass as well. So all glass can break but thicker it is lesser the chance.
Best way to tighten a bulkhead is to place the gasket on the water side and fling/nut on the outside. Hand tighten to your best then use a tool to push it just a hair more.

Correction, I meant to say over 1/2” glass. That would be a crazy amount of torque.

 

[Dr. Reef]

It's not just in torque, which I agree, in 1/2" it will be a tremendous amount but an uneven pressure from bulkhead put wrong and then added pressure from water itself will cause a crack or stress that may give over time.