Hi Jeanne, we had the same trouble years ago but we didn't have rocks or stones at the bottom of the pond which can be a real problem for ponders. After the stones have been in the pond for 2 to 3 years, fish start to get sick or water turns green or hair algae runs rampant. In the beginning the stones work to help keep a balance in the pond with colonies of good bacteria but with uneaten fish food, fish feces, or any plant material that falls into the pond and ends up at the bottom, especially if you have oxygenators the pond will soon become unbalanced as your's has become. The other thing is your filtration system.

Since this is the first year for your pond, if your filter was large enoughy for the size of your pond and the fish in it, your pond water should be good.

How many gallons is your pond?

How many fish are in the pond?

How often do you feed your fish?

Do you make water changes?

If so, how much and how often?

Can you tell me the approximate gallonage of your filter?

How often do you have to clean your filter?

Is your filter inside the pond or outside?

Yours Koily, Lorraine