OK, so I learned my lesson, went on holiday a couple of months back, came back to find pretty much every fish dead due to Ich. Tried managing with UV and Ozone - no luck, so I'm onto QT.
Everything is now in QT. I followed the Cupramine instructions to start with and hit it for 14 days - it came back on one clown fairly quickly, I messaged them and they said go for 28 days. I've been testing the copper levels and they are right. All fish have been in QT for just over 2 weeks now and the one clown still has the spots quite clearly so I'm ready to try something else.
I'm torn between going for hypo salinity and the tank transfer method - what have other people found successful? Also if I go for the hypo method what's the best thing to buffer the PH with?