Originally posted by ClarksZ06
Lowering the salinity on a 200 gallon system is not even an option. As long as I don't leave the copper in the system to long and get it out with polyfilters, carbon and waterchanges everything will be fine.
Well i wouldn't say it's impossible to lower the systems salinity...
I'd just connect the ro up to it, while draining it at the same time.
The Ro adds water at such a slow pace, that the water change would be easy on the fish. (not easy on you

)
My entire water system is 400gallons and I had this setup so that I could do exactly what I said in the case that the main display ever got ich.
What you said makes sense, especially about the tests being inaccurate. Which is another reason i'd never use copper.
So I'd say go with what the instructions say.
Also you say you've done this before...
Might I suggest a QT tank and that should reduce the possibility of doing this again.
I know QT's are pains...but what would be worse? maintaining a small tank or losing your entire display?
Just a thought. I kept my 46 up as a QT.
Good luck and let us know how it turns out.