Well, you have been at it long enough to get nitrites, so you can add less ammonia from now on. Once your ammonia goes to zero in 24 hours, you do not need a daily dose of 2ppm to grow the ammonia eaters. I would go to the dose that would have been 0.5 to 1
ppm of ammonia before you had nitrites. The more ammonia you add once it is being converted to nitrite, the higher the nitrite spike will be.
So, if nitrites are off the chart, you have a lot of nitrite, and are waiting for the nitrite eaters to catch up. Just feed enough ammonia to keep the ammonia eaters growing, about 0.5ppm (per day if it goes to zero in 24 hours) should do, or at most 1
ppm. Things that impair ammonia eaters are low pH. Below pH of 6.5, nitrification is severely impaired, and it stops at pH of 6.0. I do not know if very high nitrite levels can impair ammonia eaters, but if your nitrite is off the chart, a
PWC can't hurt. Nitrite of 2 to 5
ppm will grow your bacteria. Likewise, if your pH went down, a
PWC can help bring it back up.
Finally, extremely high nitrate levels (>100?) can effect nitrite tests, since some of the nitrate will react. Along the same lines, very high nitrites can make you think your nitrates are higher than they are, since the nitrate test measures the amount of nitrate you have by how much nitrite it can be converted into. And very high nitrite (12ppm?) can show up on a salicylate (two bottle) ammonia test, so perhaps your ammonia level is really high nitrite interference? If this seems confusing, check out:
http://home.comcast.net/~tomstank/tomstank_files/page0018.htm
I bet you have "high nitrite" interference on your ammonia test.