All products for treating ich vary greatly. We need more information before being able to give you a propper idea. The two products you list, I am unfamiliar with. Kent makes RX-P, which is an anti-parasitic and safe with many (but not all invertebrates). If you have starfish, ornamental nudibranches, sea apples, sea cucumbers, sharks, rays or other very sensitive animals, I wouldn't even recommend RX-P for you.
Let's get a better idea of what's going on before freaking out by answering a few questions.
What kind of livestock do you have, how many, and in how large of a tank?
What fish are currently affected?
What are your water parameters currently at (specific gravity, pH, nitrites - NO2, nitrates - NO3, ammonia - NH3/4?)
Is the fish new, or is something picking on it?
What are you currently feeding?
Ich is generally brought on by a cause, something outside of just the parasite, since the protozoan is generally present in all water, no matter how clean (yes, you drink ich from your tap water - funny to think about in a way). By getting a better look at the whole situation, we can get a better idea of how to address the problem, epecially if you have very delicate invertebrate specimens (*in that case, you might just want to catch the fish and dip).
Good luck and get back to us! XD
