Keeping Tape Grass Rooted

[powellmacaque]

I inherited a tank that was up and running, but only had about 3/4 of an inch of Fluorite as a substrate. The tank is a 30g tank with six Flag Fish and two Sailfin Mollies, and I can't seem to get the Tape Grass (Vallisneria Americana) to stay rooted. I doubt the fish are digging it up, so are there any ideas on how I can get these plants to stay rooted?

Furthermore, I'm trying to create a native Florida tank, so I'd like for the grass to meadow. Has anybody had this effect occur in a small tank like a 30g?

 

[fishorama]

As you know, you substrate is very shallow. Can you add some to get at least 1.5 inches, 2" would be better. It doesn't have to be Flourite but finer will sift down. Try to at least get a close color, otherwise it'll look odd. You can also try pebbles around each val to try & force it to stay down, maybe a temporary answer. Again, color match if you can.