green water in duck pond

Question
tom i have a 220 gallon duck pond with on fish in it you told me to try barley bales to prevent greem water how often do i change the bales how long do i leave them in do i pull them out as long as the water is clear or leave them in no mater how the water looks will they sourif they are in to long

Answer
Hi John,
Thanx for your question.  Leave the barley bales in the pond until they completely decompose.  It takes several months or more for this to happen.  Keep changing them as they decompose.  I would do this continuously.  I hope this helps.
Tom