I moded a 10 gallon for a refugium by breaking out the short end of a standard 10 gallon tank, then removed the black stripping on top and bottom.
Then I measured the top of the tank,I went to a glass shop and had them cut a piece of glass and drill two holes in one end. I forgot to use tape to keep my silicone looking neat which made the end product slightly less attractive. I reused the old pieces of stripping I'd taken off the bottom to reinforce the "new" top and bottom ends. This 10g now stands 20" high, 12 inches wide and 10 inches deep. when I was finished, I had a 10 gallon refuguim that would stand beside my 30 long. I'm using it now, but think it's undersized to do my 65g much good, but it has zero leaks!!!!!!!!