I always prophylactically treat quarantined fish with copper for 4 weeks. 2 weeks is too short of a time. Then they get a round of Prazipro before they have a chance at getting in my DT.
Wouldn't it be best to always do copper last, then immediately release fish into the DT or at least a new, sterilized QT? If: 1) 30 days is typically long enough to outlast the Trophont Stage (parasites on fish stage 1), 2) The Trophont - Tomont Stages (stages 1-3) can last a total of 72 days or more, 3) the Theront Stage (free-swimming stage 4) is the only time the parasites can be killed, and 4) The theronts in stage 4 are always killed by copper before they can attach to fish and become trophonts-- one would have to remove fish from the QT while being protected from theronts to ensure they aren't infected. In other words, fish would have to be removed while copper is at therapeutic levels. Otherwise, any living protomonts and/or tomonts could become theronts during the time copper is not present, presenting opportunity for the parasites to infect the fish in the QT.
I'm not knocking your procedure. I'm just trying to follow the logic behind the quarantine process in general.