I have a small pond approx 300 gallons in my backyard. What can I use to control algae that will not hurt my water lilies or other aquatic plants. I am using a bilogical filter and enzymes in the pond on a maintenance basis. We have Shebunkin goldfish in it. Our pump is rated at 1450 gph (which is rather high volume for this size pond, but turns the water over more often). It is in full sun most of the day. There is landscaping surrounding the pond. I can get a picture of the pond if it would be helpful. pH is around 7.6, Nitrate levels are ok, Nitrites are just out of the safe level, hardness is fine. Just would like to keep the algae down this year.