Whatever is in your water.
Koi do just fine in fresh water, which will have some trace levels of
various salts, not just sodium chloride, but also calcium and magnesium.
(which affect the total hardness)
Happy ponding,
Greg


"Khoa Tran" wrote in message
news:1060809216.896369@sj-nntpcache-5...
Hi,
What is the best salt level for koi pond in normal condition (not for
treating parasites) ?
Thanks in advance
Khoa