Hyposalinity question - QT tank - how fast can you lower SG?

[Delphinus]

I've got 3 fish in a QT tank right now (newcomers). I can see ich on them, enough so that I'm a little worried.

So .. dumb question here. I've never actually run a QT tank before and I've never ran a hyposalinity treatment.

I'm doing some reading but one piece of information I don't seem to see touched on in great detail (I might be overlooking so I'll keep reading but I'll ask it here anyhow), is how fast can you safely lower SG in a QT tank? There's nothing else in the tank (ie. no snails or inverts .. just some live rock and an aquaclear), so no worries there - it's just the fish.

And wow, SG at 1.008 for the target SG. Did I say "wow" yet? Yikes.

How much of a drop is too much for one day?