I did a large wc last nite 90%...redosed ammonia to 2.0ppm...just tested my water this morning...ammonia...0ppm...nitrite...0ppm...i redosed ammonia back to 2.0ppm.....now when i came home did my water test my ammonia was at 0ppm..but my nitrite was back up to 2.0ppm..why is that..now is it common to see a change like that after a large wc