Thanks for the suggestion, snazy. I have to say, though, that I'm really liking my tank now. It's the only one that is pest algae-free, and I rather like the balance. I now have 11 tiny zebra danios taking up the upper third of the water column, and that's what I was looking for. Also, the cory love to hang out in that "bare" spot in the back middle.
Honestly, with the algae problems in my other tanks, I'm concerned about doing much to this tank that might upset it's balance! I do like the idea of the aponogeton crispus though.