The lower salinity in a QT will kill the ICH tomites, after the SG
is down around 14% (I believe that is the number). ICH will die. The reason we generally don't do that in the main, is because that low of a drop will effect the LR
and inverts. In the QT, there is no LR
(hopeful), so we can lower the salinity/SG
enough that the ICH can not survive...just like a FW
dip, it just takes a little longer. That is just what I have read. I am sure there are folks that have been successful might chime in....
The reason the main is left fallow, is to starve the ICH.
I have never dealt with ICH, so I can only go on the successful stories of the folks that have gone through it, themselves.
I'm not trying to say you are wrong. I can only regurgitate what I have read at this point.