Someone posted a chipped tank. It was entirely on an edge. The tank would be fine if you cleaned the edges of the chip. The sharp edges can cause stress in the glass as well as make it very sharp. You can buy ( or used to be able to) a diamond nail file at the drug store. You can use it to file the sharp edges of the crack which de stresses the glass, it also removes the sharp edges.
I cut glass and use one to clean the edges so they aren't sharp as well. That is how I get pieces to make a sump.
I found how to fix car windshields, distress antiques and seek counseling for stress.
I gave up.
Another person was saying the old rules of thumb are silly. It occured to me I have been very successful using them, but they all go together, Pounds of rock per gallon. Fish per gallon, Size tanks for types of fish.
I learned these 10 years ago from people that were doing it 10 years before me.
Sadly if you don't go by one the rest don't work either.
It is a formulaic way to keep some marine stuff alive. It is a very good way to start off. Once you get some experience you can start to try other methods.
