This year here in the Mid West we have had a lot of problems with algae in ponds especially blanket or string algae. In part some of this is do to the weather spring was extra cool and wet and there fore some of the beneficial bacteria did not have a chance to multiply and balance the ponds before the sting algae started taking over. The algae actually is there trying to use nutrients that are produced by decaying matter and fish waste that are usually controlled by the beneficial bacteria and
aquatic plants. With the cool and cloudy weather some of the pond plants did not get off to such a good start either so it was a double whammy for the ponds.
Normally in a backyard pond if you have the right mix of plants and fish you will experience very little trouble with maintenance but once string algae takes hold it is an uphill battle. It is not a quick fix but what I have found as the most effective method is to first treat the pond with a granular algaecide specifically for string algae. Once you add it make sure you have good aeration and water flow so that the decaying algae does not deplete all the oxygen in the water. As clumps start floating to the top start skimming them off. A piece of cotton batten in the top of your skimmer will help collect a lot of the finer particles. You may have to rinse the batten out two or three times a day but the water will clear real quickly. The main thing is to get rid of the dead algae before it cause more problems. It may take two treatments to get it all. DO NOT OVERDOSE YOUR POND READ THE LABEL AND FOLLOW THE INSTRUCTIONS. After treatment wait about 48 hours and start adding beneficial bacteria I use microbial lift it works real well for me. I recommend at least once every twoo weeks adding a maintenance dose.The next important step would to be sure you have a good mix of aquatic plants I recommend you have about 60% of the surface covered with lilies or water hyacinths this will help shade the water and cut down on sunlight. A healthy pond will also have submerged Oxygenator Plants such as Anacharis or Hornwort. These are essential to good pond health.
The other important thing to remember it to keep the debris that get into the pond at a minimum skim leaves and remove dead plant leaves also do not overfeed you fish if they can’t consume all the food in 5 minutes you are giving them too much and it will quickly lead to water quality problems.
Once you have your pond in balance there really is very little maintenance the secret and trick is to stay on top of it and it is only a couple of minutes a day.