I have some fish coming soon and I wanted to get a quarantine tank setup. I had one up previously but haven't used it in almost 2 years. When I was done with it last time, I just shut everything off and left it. The water in the tank evaporated eventually and everything was just left sitting there. So a couple of days ago I filled the tank up and got the filter running again. I put some ammonia in to get the cycle started. Today I tested the water just out of curiosity. I got 1 ppm Ammonia, 0 ppm Nitrite, and 5 ppm Nitrate. I was quite surprised to see Nitrates in there. I haven't added anything to the tank other than ammonia. No starter bacteria or anything. I'm pretty sure there was still water in the filter this whole time, but I'm not sure how much. Is it really possible for the Nitrifying bacteria to survive that long? I guess it is possible there was waste in the filter to continue providing ammonia and help them survive. But that seems like a long time. Anybody else seen anything like this before? I was expecting to have to wait a few weeks to get this thing cycled, but maybe not now.