All along during the Add&Wait fishless cycling process, once ammonia is regularly dropping to zero in about a day, you should have a regular time of day (out of the 24 hours) when you add ammonia. It doesn't have to be right to the hour or minute of course but it can help the overall pattern of interpreting things if you are "regular" about it. So on any given day, if ammonia has reached zero ppm any time in the previous 24 hours, you add ammonia at your "add hour."
Just to be clear, this means that if you are in the later stages of fishless cycling and are curious enough to be testing at both 12 and 24 hours, then even if you saw zero ppm ammonia at the 12 hour test, you would still wait until the 24-hour mark, when your "add-hour" is and then add ammonia. The reason for this is so that you will have less overload of nitrite and nitrate later on in the fishless cycle. It won't slow the bacteria down at all for there to be zero readings part or most of a day.
Now as to the amount of ammonia, you are currently in your "nitrite spike" phase, obviously, and so a good tweak is to only be bringing your ammonia concentrations up to 3ppm or so instead of 5ppm. This will also help to minimize the nitrite and nitrate overload some. Its not necessary to have success but its just a nice tweak sort of thing. After nitrite finally starts dropping to zero withing 24 hours and you are waiting and waiting for it to drop to zero in 12 hours, that's the time to build your ammonia concentrations back up to 5ppm. In fact, towards the end of that last phase is really the only time, except perhaps in the very beginning, when it matters to get it up to 5ppm if you can, and of course its such a judgement call anyway that 4 and 5 often mostly look alike anyway, so no big deal.
~~waterdrop~~
