I have a tank that has been up for a few months and running smoothly.
Am=0, Nitrate =0, Nitrite=<5ppm, ph ~8.0, Calcium between 400-440, salinity 1.024-1.025, temp 79, run my PCs about 9hrs a day.
Last week on Thursday it jumped to 20ppm almost overnight, I did a 10% water change, on Friday...