@CenteelBen
Yes, you got it perfectly. When a scientists tests our tanks he will use a test based on the nitrogen scale and he/she will tell use that one ppm of ammonia creates one ppm of nitrite and of nitrate. That is because the chemical formula for all three of these things contains one N. But most of our hobby kits measure the rest of the things present which in turne causes the numbers to increase at each level. Think of it like measuring temperature in C v.s. F. Water boils at the same point at sea level whether we call it 212F or 100C. There are conversion factors for the nitrogen complex measurement scales just as there are for converting C-> F/F->C. Here is one
https://www.hamzasreef.com/Contents/Calculators/NitrogenIonConversion.php
Your added info helps to clarify what is going on on the tank. Plants change the equation. One cannot use the rulwes.mthods for doing a fishless cycle with no plants for doing the cycle with some amount of plants present. Further, just as different fish species have different tolerance levels for ammonia, nitrite and nitrate, the same is true for plants. Most plants take up NH4 while the bacteria want NH3. Because there are both forms of ammonia in a tank and that the balance is determined by the pH and temperature of the water in the tank, it is impossible to come up with rules or values for nitrogen is such cases. But too much NH3 can harm both plans and fish.
If one is doing a plain vanilla cycle with no plants, the amount of time it might take is not written in stone. Even when the same amount of ammonia is being dosed. we still cannot tell at the outset how many days it will take for any given tank to become cycled. The reason for this is really very simple when we think about it. The answer depends on how much bacteria is present in the tank when we start a cycle. There is absolutely no way to know the answer. However, we can understand why there can be such differences if we consider a simple example of two identical tanks with one difference, tank A has 10 individual bacterium for ammonia conversion at the start while tank B has 20. For this example we will assume that the doubling rate in the tanks for ammonia bacteria is 8 hours.
Consider where things will be at the end of 24 hours. Tank A doubles to 20, then 40 and finally 80 after 24 hours. Tank B however doubles to 40m then 80 and finally 160 after 24 hours. So at the end of the first day of cycling where Tank B had started with 20 more bacterium, it now has at four times that being 80 ahead. The only way we can see this might be the case is that Tank A will have more ammonia than tank B at the end of that day. If we assume the tanks need 1,000 individual bacterium to be cycled for handling ammonia, Tank B would have 1,280 at the end of day two while tank A will only have 640. Of course, in reality, the number of individuals is in the millions not the 100s or 1,000s. But this example does illustrate the effect.
This sort of potential difference also applies in the case of plants in a tank. Moreover, while plants do use ammonia, they can also be sensitive to higher levels. It can even harm or kill plants. My normal suggestion relating to cycling with plants is that the formulas go out the window and the amount of ammonia to be added is closer to 1 or 2 ppm than 3 and certainly not 4. So let's assume that one is not adding too much ammonia for plants to handle. What effect will plants have on a fishless cycle?
Since there is no formula we can use here, we will have to rely on the chemistry involved to point us in the proper direction. The first step is to establish ammonia oxidizing bacteria. But with the plants using some amount of the ammonia, we can expect the amount of bacteria needed to be much less and that ammonia levels will drop a lot faster than in a pure fishless cycle with no plants. The changes do not stop with ammonia. because bacteria are converting a lot less of the ammonia, they are also making substantially less nitrite which in turn means less nitrate. Any nitrate that might be created may not last long in planted tanks as plants may use that as well as ammonia.
Given enough live plants, the cycle can be skipped entirely. Gradual stocking will be possible almost as soon as the plants have some time to establish. This is partly due to the fact that the plants arrive with some amount of nitrifying bacteria living on them. The problems hobbyists cannot solve is what lies between no plants and a full load? What is the effect the actual plant load in a specific tank has on cycling? Again, we are faced with the need to come up with a method of answering this question in the absence of any accurate measurements. Creating guidelines and methods for doing this would require a full length article on the topic which I cannot do in a post.
