Substrate in a planted tank

When I set up my tank, I was at least as interested in having plants as I was in having fish. To that end I bought a bag of nutrient-rich substrate, which is covered with a layer of pea gravel. Therein, I suppose, I made my first big mistake. While the gravel made an attractive bed for the aquarium, it isn't the best thing to grow plants in. So while you see pictures of planted tanks in which the plants spread rapidly, the coarse gravel which covers the bottom of my tank is likely to be a serious hindrance to the development of the sort of "carpet" of vegetation I would really like. Of course, there are other hindrances - lighting and carbon dioxide. While I have improved the lighting in all of my tanks, I'm sure carbon dioxide levels are still inadequate. While passive CO₂ systems are easy enough to build, you really need to monitor pH if you add CO₂. After all, excess amounts of CO₂ could harm the fish.

In a sense I am still early in what I might consider the third stage of tank evolution. In the first stage I planted the plants I bought, and watched the fish dig them up. Then, when I salted the tank to handle my ich outbreak, I lost a lot of plants. I also kinda gave up on the whole idea. More recently, especially since I established the plant tank, I have given optimism a new shot. With the plants I established in August and September growing, and with some new plants from Houston, there's enough stuff in there to start thinking some more about aquascaping. Removing the mass of floating plants (mostly uprooted stuff) has changed the light distribution in the tank.With most light penetrating to the depths of the tank, I am hopeful that my plan to create a shorter "meadow" to the from of the tank might work. At least somewhat.
Here are a couple shots of the tank when it was first set up. The left side of the tank is still remarkably similar - the area is still dominated by the two Echinodorus plants that I put in first. While some of the Java fern (visible below the intake for the filter) are still around, I don't think anything else survives except for a tiny piece of Bacopa.
Here's the tank today:










While it's nowhere near a perfect planted tank, I think it has matured nicely.