farm thanks for the post. I am confused by your journal results as they does not match the initial assumptions in the original post. According the three fingers you were obviously cycling a planted tank. But, according to your journal, you cycled first and then added the plants. This makes me wonder why you asked about adding co2 during cycling. There would be no reason for this in the absence of plants. I am also confused by the results you reported. For one, 106 L dosed to 3 ppm with 9.5% ammonia takes 3.35 ml not .9. So I am confused by this, unless you used a much stronger ammonia. But your journal is not real detailed and this was not discussed.
Next, you show ammonia dropping but no nitrite initially. But in an unseeded tank with no plants this should not be possible. If the ammonia drops, the only place it goes is to become nitrite so as ammonia drops nitrite appears. And the nitrite then hangs around and increases until enough nitrite oxidizing bacteria have reproduced. not what you indicated had happened.
When one intends to plant 50% or more of the area, there is rarely a need for any cycling. The plants can handle most of the ammonia and the bacteria that comes in with them provides seeding for any more bacteria that shouldneed to develop. In such a tank all one needs to do is to dose 2 or 3 ppm of ammonia and test in 24 hours in order to see how much ammonia is being processed- regardless of whether it is plants or bacteria doing it.
I really need to write the article on cycling with plants because I would have suggested totally different methods for your situation. I would have told you to plant the tank, wait about 10-14 days and do the initial ammonia dose to test the tanks capacity to process ammonia. I would have told you to do a nitrite test at the same time to determine if the plants got all the ammonia or they were not able to do so and left enough ammonia to show that more bacteria would be needed. Often, even if there is a small amount of ammonia but no nitrite, what it means there are an equal amount of both bacteria to process what they can right through to nitrate.
I would have further said if the ammonia and nitrite readings after this dose and test were fairly low- clearly under 1 ppm for both measures that you had two alternatives. One is to dose additional ammonia over the next few days to encourage the bacteria to come up to strength or else to start stocking immediately but not to do so fully. I would have suggested adding about 50% of the fish and testing over the next few days and as long as you were getting small numbers to ride it out a day or two. But if you were getting 0/0 numbers, it was then safe to up the stocking.
The thing people tend to forget in the cycling process, whether plants are involved or not, is that smaller amounts of ammonia and nitrite do not last very long. Bear in mind that the bacteria can basically double in a day- the ammonia ones faster than the nitrite ones. What this means is that a new tank doses with 3 ppm of ammonia will normally process the first ppm much more slowly than the last ppm. This is because they are reproducing so by the time they get to the last ppm there are many more of them. With plants this can go even faster because as plants grow larger, they also can uptake more nutrients.
One of the key difference in cycling with or without plants again traces back to nitrite. This is most often the culprit in stalled fishless cycles. But in tanks with plants, nitrite levels will always be lower than without plants. The reason is simple, when plants uptake ammonium, they remove it from the water but then do not create nitrite the way ammonia bacs do. So every ppm of ammonia plants take up means 2.55 ppm of nitrite that wont be created.
Many of the differences in cycling issues with or without plants are related to the difference one will see in terms of readings for nitrite and nitrate. because the plants don't make nitrite numbers are lower for this and because they also consume nitrate, the numbers for this would also he lower than expected. What complicates all of this is cycling involves ammonia going in (either added or created by fish etc.) and then testing. We can not see the bacteria or count them and we do not know how much our newly added plants may take up either. Of course we do know with enough plants in a tank it wont really matter. but most folks do not plant anywhere near this heavily and most wont start with larger sizes of plants. So the only way to know how much ammonia a tank with some number of plants and bacteria present might handle is to dose to 2 or 3 ppm and test. from there we make the rest of the plan to insure the tank is safe for fish.
Of course I have completely omitted stocking levels in this discussion even though they also play a part in the process. The same tank might be ready for light stocking but not full stocking for example. However, if the fish keeper want to stock fully, this matters, if one is willing to stock in stages, it may not.
I would end by noting in tanks with no plants and no bacterial seeding that the methods here dose to 3 ppm for the sake of safety. It gives a nice margin of error so that newer hobbyist wont under cycle a tank and then try to stock it fully. And the entire process of cycling can be made pretty universal in these cases. But as soon as one brings in plants or seed bacteria, the paradigm changes. The numbers and methods for pure fishless cycling tend to become less useful the more plants and/or bacterial seeding one does. And this , in turn, means the numbers used in the cycling article may never be seen and therefore the fishless cycling road map there becomes useless. How can one add another dose of ammonia if nitrites never hit the target reading for when to act?
So I am still faced with the same situation in this regard. Until I can organize the next article in the cycling arena, how to do it with seeding and/or plants, and then have it meet with approval from the Admins and mods, this subject will never be properly laid out. My one caveat is that I expect folks who are using more sophisticated plants and more involved fertilizing and co2 addition should be advanced enough not to think that the fishless cycling article applies to what they are doing. if they do not, then they really are playing over their heads at that point. How can anyone knowing some plants can not handle much ammonia put sophisticated plants into a tank and add ammonia without checking? To me it is like folks trying to do a fish in cycle but not knowing the difference between NH3 and NH4.
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