In a perfect world, everyone would be able to enjoy their Koi swimming around the pond without the hassle of taking care of it. Since we live in the real world, ignoring your pond maintenance isn't an option. If you follow these steps, the amount time it takes to maintain your pond will shrink.
1. Feed your Koi better food
Cheap Koi food will pass through your Koi only partially digested. The resulting influx of nutrients in the pond will spur algae growth.
2. Place leaf netting over your pond in the Fall
Other than dealing with string algae, removing leaves accounts for the majority of work involved with keeping a pond. It may be unsightly, but placing leaf netting over the pond for a couple weeks in the fall will eliminate a lot of work.
3. Remove the rock from the bottom of the pond
Rock will trap any leaves that fall in the pond. Fish waste will also collect in the small spaces between the rocks. The rocks needs to be cleaned often, otherwise anaerobic bacteria will break down the waste and will produce hydrogen sulfide (it smells like rotten eggs.)
4. Add a bottom drain
Bottom drains remove waste from the pond automatically. Any waste that moves within range of the drain is captured and then deposited in the filter system.
5. Add mid-water returns
Most ponds use only a waterfall to return the filtered water to the pond. There is little or no control of the flow of water inside the pond. Mid-water returns help reduce maintenance in the pond by creating currents that push any suspended debris towards the bottom drain.
6. Upgrade your filter
A good filter system will keep the pond clean with a minimal amount of maintenance. The filter should trap waste and debris so you can flush it out with the turn of a valve instead of having to scoop it out of the pond with a bucket.