Nitrite levels to high?

Question

My aquarium is in the second stage of the "New Tank Cycle" and the nitrite levels were at 3ppm. The comparison chart I have says that 3ppm is stressful to the fish so I did a 20% water change. But I found a chart on the web that says to do a 50% water change. How high do nitrite levels have to be to really harm fish? Here is that link http://freshaquarium.about.com/library/begin/ncolornitritechart.htm

Answer 1

Nitrite stresses fish at 1.0 ppm, and can be fatal at lower levels if they are exposed for a long enough time. It's best to keep the level below 0.5 ppm.

Looks like a few more water changes will be needed.

NOTE: To prevent too much of a water chemistry change at one time, do no more than a 50% change and add new water slowly, as if you were acclimating a new fish to the tank.