I have a 50gal I have set up for some African cichlids. I filled it and began cycling six days ago. The tank previously had some turtles living in it. I sold them, then completely emptied the tank. I thoroughly rinsed the gravel, scrubbed the tank walls (no chemicals, just water).

The canister filter I have was kind of nasty, so I put new charcoal and BioZorb, but the top layer (thin spongy part) I just rinsed and left in there. The black coarse filtration part on the bottom just got rinsed too.

Then, I put three 2" goldfish in the tank to start cycling. I tested the ammonia and nitrites today and found NOTHING. Just like I have for the past six days. I'm using a high end liquid testing kit.

Why isn't any ammonia at all showing up? I've got a couple small plants in there, is that it?