I'm not sure but I would be concerned that if you had to treat for
disease or parasites that the copper or high concentration of salt
might react with the zinc.
"Don" wrote in message
...
Is a galvanized trough ok for quarantine? It is in a shady location
so temp
fluctuations won't be drastic and it is very large 7' x 3'

I have an indoor 75 gallon but for koi, the more room the better. The
residents seem happy after about a week.