dwoh,
if the gravel vac wasn't dried out before you used it int he main tank, you MAY have transferred some ich into the main tank. i'd watch it carefully. It's happened to me, but with me, it was a reused net.
my goldfish were really active and hungry at 89 degrees, but my oranda, moor and ranchu did more than fine.
you can try the heat only approach, but 1 tablespoon* per gallon (equal to 3 teaspoons) is optimal, but you have to raise the salinity gradually (or did what I do, dip a net in the tank water and pour the salt into the net, allowing it to slowly dissipate over a few hours.) the goldfish adapted realy well to the salinity and they were more active even though they were completely covered in ich. Don't keep the salinity too high for too long though. only replace 75% of the salt every time you do a partial water change.
Recently I had the heat resistant strain of ich, so tough to get rid of w/o salt.
hope this helps and good luck.