How Long?

I don't know if this is any help, but being something of a hoarder I have the leaflet that came with a bottle of Interpet med though it's probably quite old now. Under the entry for the velvet/slime medication it says:
"the treatment remains active for several days ensuring all the parasites are killed" though it doesn't define how long several days actually are

and
"before re-dosing.....you should wait a period of 7 days then carry out a 30% water change before dosing"


From that I assume the condition should have cleared up within 7 days but if it hasn't by then, do a water change and add some more.