Little spikes (adjustment bumps) can be normal on a new tank with new inhabitants every time you add or on a established tank if surpassing bio load limits.
I'll try to explain real simple like.
Running tanks have a established bacteria count for what's in it. As you add or over feed you introduce more than the bacteria can process at that moment, your test kits will start to pick that up. As you continue the bacteria will grow in numbers to handle the new bio load until saturation (no more surface area to grow in tank) that is your ceiling. When you surpass what the tanks bacteria can handle you will start to see continuous spikes after feedings that won't go all the way back down and will register all 3 parameters when testing. When you get to high (over do it, instant huge load) it becomes like a teeter totter, just balancing, it will either work itself out, or crash. When you start to register all 3 during weekly testing you have over done it and need to back off on feedings or get rid of a couple fish, you're now on the border line. 1 mistake or accident at feeding time you may crash.
When you can register ammonia only, you have caught the start of what happened. Which would mean look back up to 7 days prior for what you changed/did.
Super simple explanation is:
Ammonia = weeds, bacteria = help. 1 help can remove 1 weed per day. You only have room for 50 workers in your tank. You have 4 weeds per day and 4 helpers to remove them, everything is balanced. You add food/fish and the next day you have 5 weeds and only 4 helpers. So only 4 weeds get pulled and 1 is left. You ask for more help the next day and get 5 workers. The next day they pull all 5 weeds. So everything is balanced out now. When you get 51 weeds and only 50 workers can fit in you tank, then the weeds start to take over and we don't have enough room/help to pull them. Also remember for every new worker that comes into the tank, they will need a couple days to acclimate to there new job, so it might take them a couple days to get on the ball.
After the weeds are pulled , they are now relabeled to compost (nitrites) and the process starts again, same concept.
When the compost is put out, it then becomes rubbish (nitrates) in which we only have so much room on the curb for before we manually have to remove it.
When we start generating to many weeds, compost, and rubbish in the tank it will become overrun, with not enough help to manage it. Now it starts to pile up, if left unchecked you end up with a land fill.
Prime would be like extra help in the bottle, they remove 1 weed each, then leave. So if we had 101 weeds and 50 workers, the prime would add the other 51 workers to pick the extra 51 weeds. After they pick one, they leave. So after all the prime workers pick weeds or leave, you would want to be back down around the max of 50 weeds/workers in the tank.
And as CELL had said, each tank will be different. No set limit on what can be added, some general rules of thumb for initial stocking. In some tanks 2+2=1, others 2+2=4, and then the 2+2=5 in others. So as long as 2+2=4 or less, everything runs like clock work.
