I might be a little late to be of any help and from only having read the first post but I was also given horrible advice from people I trusted and started off with a tank that had been run for two days with no fish (or bacteria supplements) and then added fish to it. I noticed small spots on the fins of my fish from day one but were told by people on online forums that is was most likely just calcium spots. They never looked like anything I could google or anything the forum friends could recognize so I took it as me being nervous and jumpy. But when the dots become more (still not stronger however, they looked like water that dries on the sink and leaves a calcium stain) I just went with my gut feeling and later that day got it confirmed by a pro shop keeper that it was in fact a very early case of Ich. I treated my entire tank that hadn't had a chance to cycle but I didn't lose a single fish (and they are freshwater angel fish btw) and the tank cycled within a few weeks after that just as expected. The white spots gave in after about 24 hours and and since the fish are spotless and since cycling the tank has been perfectly stable.
Though water changes were a part of my daily routine, it was like brushing my teeth. I carried so much water daily between the tank and the shower and not just during the med treatment but afterwards as well, I naturally got a spike in every thing that could spike (my nitrite readings were terrifying at one point). But in the middle of my feeling bad mixed with total panic my fish had a growth spike and grew several millimeters in one day, it was surreal!
So I apologize if I'm totally off with my post, heh, though hopefully it can shine some light on it all, raising the temperature like I can see people have already recommended is great. My tank is always almost 30 degrees so I didn't have to do anything about that and I do believe that helped a lot in killing the Ich. Salt helped a great deal as well with the spike that came later, I added an appropriate amount to every water change. My fish never showed any signs of suffering through the whole thing, they had the most impressive growth spikes during all this. Me and the water bill however are a whole other story ;D