Answer: Healthy fish pond water should not be super green, however it will never be totally clear, either. You should not be able to see your hand when it is about a foot down from the surface.
When you start a new pond, it goes through an adjustment period. It also goes through an adjustment period every spring. At these times, it may turn cloudy or greenish but it should begin to clear somewhat as the plants grow, the temperature stabilizes and the pond comes into balance.
To come into balance, there must be an ample amount of underwater oxygenating plants to help clean the water, there must be surface plants such as water lilies that shade the water, and there must be an appropriate number of (not too many) fish. Very often there are either too many fish for the size of the pond, or the fish are being overfed which contributes to an excess of waste and nitrogen in the pond. This fuels the algae which causes the water to turn green.
If you have planted your pond with oxygenators and surface plants, do not overstock it, and are patient, then it should balance itself. (Unfortunately, every time you drain it or make adjustments it restarts the balancing process.) One other factor that can help during the heat of summer is to shade the pond at midday or during the early afternoon. This helps a smaller pond to stay a little cooler which is less conducive to algae during the summer.
I hope this helps you trouble shoot.
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