When doing reflections remember to make the reflections of light colored objects darker and reflections of dark objects lighter.
You can observe this yourself next time you are at a marina. Look at the reflections of the white boats and you will see that they are be darker than the white of the boats. If there are any black boats you will see that their reflection is lighter than the black of the boat.
The reason for this is because the color of the reflection merges with the color of the water, a kind of averaging effect.
Obviously this applies to all reflections not just those of boats e.g. the sky, buildings, trees, etc.