I am in quite a similar situation. Save for the fact that I have a good amount of experience with aquariums overall, this is the first real plated tank I have attempted. The only advice I can offer with certainty is basically echoing Ram. Check all your minerals. Plants need these, and to a varying degree based on the species. Also Nitrogen, which equates to nitrates in a properly cycled aquarium, and phosphates. Being able to test all these these helps greatly. Gas exchange is also a key here. In a "normal" aquarium, people use an aerator to disrupt the surface tension. To release the dissolved Co2 in the water into the air. But what this is really doing is normalizing the gas in the water with what's in the air. If you come up with a way to get more Co2 in the water than is in the air, you will actually loose it with an aerator, as the basic concept of equilibrium will take over.
I'd like to hear of what you do, and I will do the same (as well as anyone else that si doing similar things). I need to figure this out too.
On that note, does anyone know of a reliable way to actually test for Co2 past the conversion charts?
