It looks very nice.
As for your algae problem, get plants in there. Plants help to balance out the system. Also, be patient. A pond usually will turn green in the spring for awhile and then clear up. It will often turn green again in the fall. You'll see this when the weather makes its shift from cool to warm and warm to cool.
Also, I can't tell for certain from your pictures but do you have rocks on the bottom as well?