Hi Arnaldo24, I'm in the same situation currently and would like to share my experience. My DT has been fishless since first week of November 2013. The standard time to wait is approx. 3 months, however, I was out of town and traveling a lot and didn't have time to restart my QT.
Yesterday I restart my 20g QT tank. I lost almost all my fishes due to ich. I did QT at first, but it wasn't hypo nor Copper, I just
observe and then release into DT after 2 weeks. Bad idea, now I know better.
I have lots of cupramine, but I felt that using it was the last nail in the coffin. Those fishes that did survived the last and final outbreak of ich in the DT eventually succumbed to the cupramine treatment in the hospital tank. I followed the directions exactly as stated. I don't know if it was already too late for the fishes when I break down the DT to capture them, or if it was the stress, or the cupramine. I guess I will never know.
Over the past 4 months I've been planning how and when I will restart the QT. When the first fish is finished with QT (4-6 weeks from now) it will be 5 months since the DT will be fishless. :thrash: Hopefully all remnants of ich is long gone.
And although I've had 4 months to plan, I still haven't decided whether to go copper or hypo. The biggest issue with copper is that its not safe for fishes, its toxic, harmful, stressful, and according to what I read it leads to lower appetite. And the biggest issue with hypo is that it needs to be accurately maintained 100% of the time. What that means is that I need an
ATO on my 20g QT tank!
By this weekend I will decide if to go hypo or with copper, or maybe both? I thought of doing 1 week prazipo, 2 weeks cupramine, then 4 weeks of hypo. Don't know if anything is wrong with this regimen. But maybe I will soon find out. I should start my own thread...