No, I had purchased a bottle of tint for the concrete, but after the first coat of just plain concrete decided I liked it the way it was. But, the background came to a sad demise and will be picked up in our weekly garbage pick up tomorrow.
If you do some searching (sorry i dont have any links) you can find information on DIY rocks. It's huge in the SW reef world. With out much effort you can create some pretty neat rockscapes out of concrete