I’m replacing a 5 year old 46 gallon bowfront, and I really like the look of tanks with an all sand foreground. For the next iteration of this tank, I’m creating a 2-3″ band in the front of the tank to be filled with pool filter sand. My plant substrate is Flourite, and obviously those aren’t going to stay separate for long, so I’ve created a border:

Gorilla Glue is great for attaching things to glass!
First I drew a line across the front of my tank using a book as a guide. I placed it against the glass, then a sharpie against it, and slid them both together along the curved glass. Then I went to Home Depot and bought some clear drawer liner and cut a 3″ strip in it. Getting it to stand in place was tricky, so I scotch taped the ends up and reinforced the middle to be sure. I then put a line of Gorilla Glue down the line that I drew earlier, moving the liner out of the way slightly, and immediately moved the liner back into it. Gorilla glue is so cool, I bet it was free standing within a couple hours.
The idea is that this will keep my Flourite and sand ALMOST completely separated. When I fill the tank with substrate, I expect that there won’t be enough to cover up all the plastic, but that’s OK, I can always trim it down! The plan is to let Glosso and H. Roraima overgrow it and hide the border, but we shall see.
I’m optimistic that in the absence of fish that root around this will stand the test of time. I’d love to hear your comments.
BTW – The cable you see glued down is a Hydor undergravel heater. It was the same basic process for getting it glued to the bottom. All the clips that came with it are in the gravel in my running tank!