I love how people think they never cyled a tank or never used ammonia. Nothing could be farther from the truth. The term cycle a tank became used to mean adding ammonia to get there. But lets get something straight from the get go.
There are multiple ways ammonia gets produced in an aquarium. it is not limited to just adding it. Fish make ammonia, decaying organic matter makes ammonia and this include dying plant matter. Even dead microrganisms make ammonia. Soi if we want to keep living things surviving in a tank,, there must be a way to handle ammonia, Pretty much, all the plants we might put into tank come with the microorganisms which handle the nitrogen complex, living on them.
However, handling ammonia is what I consider the term cycling to mean. Live plants are very effective at handling ammonia because they love ammonium. However, they do not do so well with ammonia as NH3. If levels of ammonia get high enough your plants will die just like your fish will.
There is only one way not to :"cycle" a tank and have it be safe for the fish- big water changes almost daily. But consider nature where ammonia is also being created in bodies of water. Unless something deals with the ammonia, most living things would die from it. Nature is smarter than most fish keepers. It evolved methods for dealing with ammonia before there were people. It is done by both plants and microorganisms. And, just as the case in aquariums, it is possible for there to be mostly microrganisms when there are not plants or sufficient algae, which we mostly may not want in our tanks. However, many keepers do want some amount of algae.
How one goes about making as tank ammonia safe varies. What I do know is, no matter how many live plants one has in a tank, you still have some amount of microorganisms handling some of the ammonia. These want the real deal- NH3. Plants want NH4. In tanks with a pH low enough to make all the ammonia NH4, the bacteria can switch to using it but do so much less efficiently.
So no matter what one posts about not doing a cycle, they really are doing one just using a different method than just mocroorganisms. There is one big advantage to doing a fishless cycle without having any plants. When it is done, one can stock a tank completely all at once. Of course, there ae some fish which need an even more mature tank to thrive. Just because one can cycle a tank in a matter of days or weeks, this doesn't mean that this is what will ultimately be all that is needed in a tank to make it the best it can be for all species which have similar parameter tolerances/needs more time is needed for this.
While plants use NH4, they don't make nitrite or nitrate. That is the way the microorganisms work. and since there are always some amount of therse in even the most heavily planted tanks, there will be some amount of nitrite and nitrate created. The plants do not use nitrite but that do use nitrate, especially when ammonia is in short supply. In a heavily planted tank any nitrite created will almost instantly be converted to nitrate and then this is gobble up by the plants and is also instantly used up. So, in a heavily planted established tank one may never test any nitrate being present.
When I did my one high tech pressurized CO2 added planted tank, I used to add potassium nitrate among the other ferts I needed. In tanks with close to a neutral or higher pH there will be some amount of the ammonia in the form of NH3. There is no way around this. No matter how many plants one has they will not be using this. As they use the NH4 in such a tank some of the NH3 present will become NH4. the porblem is the NH3 will still exist if there is nothing to use it. Thankfully, there is assome amount of bacteria in all planed tanks and they will handle that NH3.
I stopped cycling tanks individually a long time ago. Instead I ran bio-farms and cycled filters. I actually began by using a tank to keep filters cycled. I would dose that filter tank with ammonia to hold keep the bacteria awake and working. Soooner or later, because I was ramping up my tank numbers, having a few fully cycled filters available but not on going stocked tanks, this was a big help. From there, it was easy to start cycling from scratch using a bio-farm with nothing but water, a heater, some crushed coral, filters and added ammonia. The bacteria need inorganic carbon which includes carbonates and bicarbonates and which are what makes KH in most tanks.
When I needed to set up 6-8 new tanks it was a lot easier to cycle the filters in one tank than to cycle 6-8 individual tanks. I could cycle those filters in 10-14 days but single tanks took longer. Right before teh bio-farm filters were fully cycled I was adding 20-25 ppm of ammonia to the tank daily, but in several smaller doses multiple times. If I added it all at once, it would have harmed or killed that bacteria and would have attracted different ammonia oxidizers. They would be more like what is used in waste water treament. This is why for the ammonium chloride solutions we are told not to allow ammonia to exceed 5 ppm as ammonia-N. This would equal about 6.4 ppm om the total Ion scale used by most hobby ytest kits.
Most, but not all of my summer tanks were without plants. However, some did have them. For the pleco tanks there were none but for Q tanks for community fish, I always used live plants.
Live plants are one of the best filters we can have. But not all tank have them. None of my plecos tanks use live plants. The lightd on them are only on when I have to work in them. otherwise they only get ambient roomlight, often this is sunlight.
So the next time I read about how somebody doesn't cycle their tank because they have so many live plants, explain to me why you have to add fish gradually if the plants make the tank fully cycled. Using my bio-farm method I can fully stock multiple tanks as soon as I have enough bacteria thriving in the filters. I also seed live bacteria and archaea. When I need to cycle a single new tank, I usually also use some live plants as well. But not for the pleco tanks.
Live pants make the best filtration, but if one doesn't want or cannot have them, the next best form of filtration would be a Hamburg Mattenfilter.
(edited for typos, bad spelling and to fix bad sentence structure)
