First, welcome to the forum, sorry you are off to such a rough start.
i moved the remaining fish to hospitol tank and put some kind of copper medication.
Good move, but what kind of copper and how are you testing for the treatment level?
im still treating the main tank with kick ich i. i
Run some GAC
and get it out of there, it is doing you no good. The 6 week fishless time will allow the parasite to die off from a lack of fish host, that is all the treatment you need for the main.
i also lower the the salt level to 1.020.
Go ahead and raise it back up to normal level, it is not nearly low enough to have any effect on the parasite and all it is going to do is stress your inverts.
Just treat the fish in the qt
tank (make sure you get the copper test kit to help monitor the copper level) and leave the main fishless for 6 weeks, IMO
4 weeks is not long enough. This should do it.
Also for the future, make sure you qt
all new arrivals for a 4 week period before adding them to your main. It will help keep the parasites out of your system.
I would also look for another LFS
, it looks like you are getting some poor advise from this one.