I may pic up some guppies tonight and if I do they'll go in my hospital tank where I keep my snail. However, this tank isn't heated, it's at room temperature. After QT I'll want to move them to my tropical tank which is 3-5 degrees higher than the hospital tank, will that be too much of a shock for the guppies to move to? I'd float them in a baggie for a long time to adjust to the temp change, would that be ok?

I think that the temperature change should be fine. To make things go even smoother, though, I would use this method: Float the bag in the tank, and every five minutes for (about) an hour, add small amounts of tank water to the guppies' bag.

That helps the guppies to adjust to the temperature, as well as the tank's water chemistry. I do that now when I add new fish, no matter what kind. (I orignally read it on a site about neon tetras, but I figured it can't hurt to do it to every fish.)

And BTW, good for you for QTing the guppies! I'm bad and have never done that.... but I don't have a spare tank. Guppies are really neat fish, I would be so excited to get some!

Thanks for the advice. I learned my lesson with QT when I introduced some non-QT tropicals last year and within 48 hours almost all my fish were dead

A 3 to 5 degree differents in temp. is nothing. It is more important for them to adjust to the water chemistry.