The secret to maintenance-free ponds is in developing a healthy, balanced ecosystem that virtually takes care of itself. Ponds, like aquariums, need a little help to get started. Unlike aquariums, it is easier to develop the care-free ecosystem in a large volume of water than in a small tank. Begin by understanding the cycling process. Chlorine and Chloramines are toxic to fish and not healthful for plant growth.
Some water even contains heavy metals.
Always treat new water with toxin-neutralizing products. Now that you have clean, toxin-free water, you need to start some beneficial bacteria growing in the pond and in the filter. There will be plenty of waste to de-toxify. Fish eliminate in the water and plant material and excess fish food fall to the bottom and decompose. If not properly turned into beneficial products, your pond will putrify and die.