False Positive Nitrite Test - Update

Nitrite in this tank is now zero; it began dropping dramatically three days 
ago and has been plummeting ever since.  The log phase of bacterial growth 
is some kinda impressive.

For everyone's info:  I removed the coconut shells, soaked them in 
dechlorinated water and then tested - no nitrite.  At that point I put 
them back in the tank.  Nitrite began falling slowly at that point, so I 
didn't bother to isolate the driftwood for testing.

So what I've learned is this - toss in some dying plant bits, a little 
bacteria in a bottle, don't filter for a few days and voila - 
"artificial" tank cycling.

Thanks to everyone who offered suggestions and ideas.