My pond has been pretty clean for many a year - but this year the water quality is looking decidedly murky, and whilst in the past I have done partial water changes, I think this year I am going to clean out 90% of the water and debris. I plan to put my koi in a temporary pond whilst I sort it all out. Anyone done this - any tips/tricks or concerns I should consider before I start. I also plan to give the filtration system a good purge as well.