Very cool. My tank (plans posted here many months ago) still hasn't taken off, but I'm moving towards a half "reef" (simple reef for now) half seagrass setup. More details once I actually get a tank setup...... (we're doing a lot of rennovation in the living room of the 2BR/2BA apartment now. I'm thinking of setting up a tank in some obscure nook. Either way, build thread will come once tank is setup........).
How deep is your sandbed?
How did you get the Johnson seagrass and codium? I'm not finding them commercially, though I do local source for Thalassia and Syringodium from someone who grows it locally (4 inch sandbed no less).
And I guess the next question, just out of curiousity where in VA are you? (i'm in Fairfax)