hi 3ndl3r
sorry about this you say you dont want a uvc but is your pond filtered?
dont forget you will need to keep replacing the bail through out the year for it to work and stay on top of the algea, you could also add some barley straw extract to help speed up the process and get on top of the problem,
barley straw needs to rot down for it to release the extract that helps clump the algea ,so a boost of barley straw extract will help till the barley straw rots enough to take effect which could take from a few weeks or a few months to take effect
you will also need to add enough bails to treat your pond volume one bail may not be enough .