I do use dunks or I would get larvae. Even with the fish in there I seem to need them. Cleaning it is a major pain. Pump out most of the water and scoop all the crud from the bottom that has built up. Then when I put water back and make the filter take care of getting it the last stages to clean. A pond is work but it is so nice that it is worth it.
Oh if I turn the pump up to fountain, then I don't need dunks as the water moves.
