Hi Mick

Good guidance here on Virkon aquatic and other treatments by Malcolm Green who is very well regarded in the koi community.
Malcolm has previously done a really interesting and informative talk at one of the YKS winter meetings.

https://www.koicarp.org.uk/medications%20and%20their%20uses.htm

Click the link below for YORKSHIRE KOI SOCIETY YouTube we will be regularly making short videos Tony https://www.youtube.com/playlist?list=PL9Tw9dIe3WGye7_JNvvflzY5_nYIiwRGj