Japanese Koi

Question
I have 2 Japanese Koi that I have had for 5 years.  I put them in an outdoor pond in summer and bring them in for the winter.  Just recently found out you can leave them out all year around.  I live in up-state NY where it gets very cold in winter.  In any event, only until recently I cannot keep my tank clear.  Don't know what I could be doing wrong but I am getting very frustrated.  Can you give me any clues or suggestions?

Answer
sounds like a bacterial bloom. Greyish white water is bacteria, and green is algae.
Make sure you do water changes and have good filtration os that there is no waste rotting around. After some water changes, the water should get clearer.

good luck!