Hi Viper,
I have a Rio 180l. It's my second tank and it has been up and running for a month now with mature filter media. There are currently a few fish in there due to necessity, so meantime, we have a pea gravel to the back and sides with sand in a kind of arc to the front. There are two substantial pieces of bog-wood running the length of the tank, Amazon swords planted across the back wall with a small group of pygmy swords in centre between/under the bog-wood. I did try to get a photo of it, but it was rubbish...will try again later.
I haven't a clue about Co2, but I am happy to install it once I have some kind of understanding, at the moment I am using seachem tabs, if I only knew exactly what I need, Co2 wise, then I'd be laughing. I like my bogwood, but would prefer to put some moss over it..Ricca, I think. The overall image in my head is fairly heavy planting which utilises the height of the tank in areas for aesthetics, cover and tank division for the fish, but I want to provide some free swimming area too. One of my problems being, I don't know if I need to remove the current substrate in order to plant out properly? I'm guessing the answer is yes.