What you have to look at is how ich lives and dies, It grows on your fish while feeding. This is the only stage of life where it can feed. It then falls off into the substrate and reproduces. Then it hatches and goes freeswimming looking for your fish. it cannot live long without a fish dinner so. You transfer fish and filter to the q-tank, the main tank the ich dies by default because there are no fish to eat. In the q-tank, you treat either with heat and salt or with heat and meds. I prefer salt it will do the job, but malechite and other meds do the job as long as the tank is reasonably clean, so it's your choice.
now once the q-tank has been treated and gone for 2-3 weeks with no sign of ich (don't forget flashing and gill scraping are signs) then there is no ich living in the q tank, and as said none in the main tank. No teardowns necessary. then transfer things back to the way you want them. there literally will be no ich living anywhere in your house at that point.
Now, if you are not looking at raised grains on your fish, you are probably only seeing the wound left by the ich. if there is no ich on your fish, the heat and salt should keep it from coming back to your fish. You will want to watch the wounds, some fish never show wounds, others can develope secondary bacterial or fungal infections. I haven't had to fight these yet, but there are a lot of products to deal with them, just try really hard to get an accurate diagnosis and treat for exactly what yu think you are dealing with. be very careful with anti bacterials because many of them kill all bacteria including your bio-filter and then you have to recyclethis may prove to be a necessary evil, but try to avoid it, and don't do anything quickly, research repeatedly, and diagnosee carefully. I have found over the years that it is esasier to kill fish with meds than to kill them with infections. Fish have immune systems also and most will heal in good water Just watch them closely.
Dave.
