There is this type of salt called "aquarium salt" which you can find at any fish store or large chaine pet sotres. Just add about half of the recommmened dosage, and keep your temp at the same range you have now.
80 to 85 thats a wide range. ick does not do well over 82. it will not survive at any thing over 82. What you can do is lower your temp below 80 for a day then raise it up slowly until it reaches 83- 85 and let it remain for a day or so. this should stop it.
You can use table salt and depending on the type of fish you will want to gradually raise the temps as near as possible to around 85F. At 85F and above most strains of ich could be killed by heat alone. Also remember to raise the aeration in your tank if your raising the temps.
I think most of those fish shouldn't have a problem with it as long as you run extra aeration. If you see signs of stress from the higher temps you might want to bring it back down a few degrees.