muddy water and koi digging up the lillies

Question
I have a small pond, 15 ft x 8 ft x 3 ft deep. It is 3 years old now, and this year it has been increasingly getting muddier and muddier. I noticed the koi digging in the lilly plants, so I re-potted them and put stones on the top of the pots. That didnt work and now I have all the dirt that was in the pond pots floating and settling through-out the pond making it impossible to see the fish. Every time they swim and flick thier tails the silt gets worse. Do I have to drain the pond , clean it and start over again. I tried to clean it by draining it down about 10 inches but when I filled it back up it got worse. I need help as I enjoy watching the koi swim around and now I cant see them except when they come to the top to feed. Any help you can offer will be greatly appreciated.

Answer
Hi Dennis:  You can add a layer of gravel to the bottom that they can sift through. Koi love to scavenge for food so this is probably what they are doing.  You can also try to feed them a bit more and see if that cuts back on their foraging activities.  If you have sludge on the bottom of the pond you can remove it with a siphon tube or even a pump.  The pond will remain cloudy until the mud is cleaned... dave