Not that this has anything to do with this post...however, in one of my tanks I have straight sand (well, black diamond) for substrate...no dirt, no nothing. It is easily the cleanest, and easiest to clean tank I own. Instead of planting it like the rest of my dirt tanks I have been playing around with potted plants Like aXio
said. It and it's working really, really well.
If (when according to Paul) I get discus this will be how I run that tank.
Got to Hobby Lobby or wherever and get the smallest little clay pots they have. If you find the small ones, they are short enough to be hidden (covered) by your substrate, depending on the amount of sand you have naturally.
Many many benefits.
You can plant the plants in dirt (they like that) with out "dirting" the tank.
You can fertilize them easier (root tabs into the single pot).
You can rearrange the plants everyday if you want, as you get new plants or as plants grow.
You can easily remove all the plants from the tank for a thorough cleaning/vacuuming.
You can move them easily from tank to tank, sell them easier...etc.
It's the bee's knees. I have half a mind to redo my 90 like this. The only real down fall I can see thus far is you wouldn't really be able to grow any kind of carpet, but still you can make some nice "floral" arrangements. Who put's carpet in a discus tank anyways.