Welcome to Fishlore.
The two most important things for treating Ich are: Temperature (I think the technical cutoff for the parasite's ability to reproduce is 82.5) and water quality (which doesn't affect the parasite, but poor water quality weakens the fish's immune system, making them more susceptible to disease).
You've got the first one.
The second is going to be a bit more difficult. Without knowing the numbers of fish that you have, this is only a guess, but I'm going to go out on a limb and bet that your tank is overstocked. The guideline is 1" of adult fish for every gallon of tank that you have. I know that the pleco alone takes up 18" (unless it's one of the smaller breeds), and the silver dollars and the scissor tails both get pretty big, so if you have multiples of them, it's going to be overstocked.
Further, your tank is only a month old, which could very well mean that ammonia and nitrites are building in your tank, weakening the fish even further than simple overstocking will cause.
Do you have a testing kit for nitrites, nitrates, and ammonia? If so, what are the ppm ratings of each of these? If not, I suggest you get one (liquid-type, rather than strips) and then read this
http://www.fishlore.com/NitrogenCycle.htm
The only way to maintain water quality is to do partial water changes. Until the nitrogen cycle is complete, I suggest daily changes. Once it's done, you'll want to do them often enough to keep the nitrate levels below 20.