Cutting 3/8 glass

[sphelps]

I can tell you right now you will have a very hard time cutting 6" x 48" off a 3/8" piece of glass that size. And that's if it's 2 feet tall because a standard 75 gallon is only 20-21" tall. Glass shops have a nice cutting table to do these kinds of cuts, it would be very difficult to do this with a standard glass cutter and table. Even scoring the continuous line 48" will be hard, I would recomend rethinking your plans. Perhaps seeing if a glass shop will do it for you, or build a new sump from 1/4" glass which will be strong enough provided you used baffles for support.

Also keep in mind that if a tank is built well, taking it apart is very difficult without chipping the glass.