It's fall, and lots of Koi keepers are preparing their ponds for the winter. One of my club members asked me how much salt they should add for the winter. My reply was NONE! Read why by clicking on the title or picture...
Generally speaking (there's always an exception) - salt should be used in sick tanks and Quarantine tanks, but not in the pond. There are so many reasons why salt is BAD in ponds.
1. Harmful to plants over .2% (2 ppt or 2000ppm)
2. Reduces freezing temp of pond, such that tissue damage to Koi may result
3. VERY hard to remove - think how many 50% water changes it would take until you got it down to less than 10ppm if you start with .6% ! (answer = 10!)
K.O.I. has an EXCELLENT FREE! ebook on the subject, called "Cold Water Effects" by Richard Carlson - please read! You can download it if you go to this page: http://koiorganisationinternational.org/?q=ebooks-0
There is also another EXCELLENT FREE! ebook called "Coming Out of Winter" by Richard Carlson which should be required reading for anyone who lives in an areas that has freezing temps!