I have had ich in this tank before and fish are all fat and healthy and with uv, selcon, and garlic i made it through the last outbreak that lasted about a week. Just never seen it come and go that fast.
Do not assume its gone, at least yet. Often with lights out , the parasite will drop off into sand and reproduce and come back on the fish in numbers. Other than UV, are you medicating?
That is very common. When ich first gets started, all of the parasites are the same age and are in the same point of their life cycle - so the trophonts drop off at the same time. Later on in the infection, the parasites become out of sync and you then see spots all the time.
