Also, place somewhere that is not under a plant that will rain leaves into it it. Now you need some aquatic plants. I'm sure they'd be happy to share some of their hyacinths as they are prolific growers and need to be frequently culled. Another thing you might want to get from your pond friend are some water snails. You may buy these from your local aquarium supply store but they make baby snails so fast that your friend may want to give you some of these as well.
Snails eat the waste debris that collects in the pond.
Finally, get a few mosquito fish from your local Department of Water and Power or other local environmental resource. Now you have a living biosphere which should require no further work from you. The plants will produce the oxygen for the fish, mosquitos and other insects will produce the food for the fish, the fish in turn will provide waste materials which will feed the plants and snails. We put rocks and pebbles in to cover the bottoms of both containers, and some seashells for visual interest. Both containers have hyacinths and water irises.