What's your take on preventative dips?

[aquarius 1]

I'm moving 4 fish from QT to the main tank this weekend. (Powder Brown Tang, Koran Angel, Niger Trigger, Hippo Tang) I had ick so I took the fish out and left the tank fallow for a little over a month and gave the fish a cupramine copper treatment in QT. When putting them back in the main tank, should I do a preventative dip to ensure that they're clean of all parasites when going into the main tank? I could do a fresh water dip, a formalin dip, or a dip-away-dip which is used as a preventative dip. I know that dips traditionally stress fish out but does it do more benefit than harm?

 

[flamehawk]

AQ1- If you plan on returning these fish to the same overcrowded conditions of the past , then you have not eliminated the root cause of all your problems. Unfortunately you will be right back to having problems soon. I know you are aware of this so one has to wonder why corrective action is not taken? If you can't afford an upgrae then return to LFS for credit or post for sale. Less hassle for you and better less stressful and thus less decease living conditions for fish.
I just wish I could convince you to address root cause. This is sincere and not an attack of any kind.