OH, I see. We thought you meant white edges. Yah, white spots are usually ich.
Be careful using that med. Coppersafe is a harsh med (though it's the one I've used for ich) and fish can be particularly copper sensitive (and inverts more so).
Follow the directions very carefully. Keep the lights off a bit more (supposedly ich in the freefloating stage is attracted to light. So they swim from the gravel to the top of the tank and may find a fish host along the way. with the lights off, they're more likely to stay at the bottom).
I'd also raise the temperature VERY slowly to about 85F.
The fact that your tank had measurable amounts of ammonia after four weeks means that it somehow hasn't finished cycling or that you are overstocked and the filter can't handle the bioload - or that you're overfeeding too much.
After the fish get better...I suggest trying to figure out what caused the ammonia spike...maybe increase water changes...
As an aside...make sure you know exactly what the disease is before you add meds to cure them. Especially before adding something like coppersafe, which is pretty harsh.
Good luck