A few things I notice.
1) the HOB filter on the back is making your co2 unit do very little compared to what it would do without the surface agitation.
2) I believe I see bubbles in the back, which if these are from the co2, they need to run through a diffuser or a reactor. If they are from a bubbler, that needs to be turned off.
3) Several of the plants are still in their emersed form, and their leaves will die off. DO not throw the plants away, just pull the dead leaves, and the plant should come back.
4) You are using just a basic gravel. Are you using a layered substrate? I hope you are using some type of fertilizer. Greg Watson's ferts are the best for the money, and offer the most control over specific nutrients.
5) You have several echinodorus species, which are primarily root feeders. They will not take up many nutrients from their leaves, and as such need a good plant substrate, or root tabs.
6) As you tank has only been setup for a short time, you need to make a LOT more room for the plants. As they grow they will shade each other out, and can kill each other off. Allow more space for them to grow in. This will also give you a more natural looking tank as the plants grow in on their own.