Since I've got some time in my schedule right now, I figure this is a good time to go in depth a little into the Principles of The Method.
Let's start at Principle One. All organisms are Malthusian in nature. They will grow and invade to the very limits their environment will permit them.
Unlocking the understanding to this method is key for your success.
What is Malthusian? Malthusian means that a population will expand to the very limits that it's environment will allow it.
Let's dial back the clock to a high school biology experiment (you probably came across this during the section on genetics due to their fast rate of duplication) for illustration:
Fruit Fly eggs are placed in a vial with about half the container filled with food.
The initial eggs will hatch in the land of plenty and immediately begin to reproduce in their new environment.
Each female will choose a mate, lay eggs and the second generation is born. Then the second generation will repeat the pattern and produce the third generation, (likely with mixing of generations, but let's keep it simple) and so on and so forth.
Now, as generations are produced, the food supply begins to go from bountiful to steadily declining as the higher and higher rate of population begins to inhabit the same space and same declining food source.
There are a few distinct points here in population relative to resources (food), space is nearly irrelevant:
1. Too Much Food, Too Few Flies
2. Food Source Availability = Fruit Fly Population (balanced, sustainable as long as the rate of death = rate of birth and the supply of food is maintained at this same level).
3. Too Little Food, Too Many Flies = the population begins massive die off, food source begins a rapid decline.
4. No Food, Too many flies = the food resource has been rapidly depleted, leaving an over abundance of flies, which now feast on their dead brethren to attempt to live.
5. The ecosystem has collapsed and all of the fruit flies are dead. Apocalypse.
What this means is, organisms will continue their bid for survival as long as possible, using up as much resource as possible, and can only sustain their growth to the extent to which available resources (food, nutrients, etc) equals sustainable population.
Let's apply this to the planted aquarium:
Micro-organisms: Micro organisms will grow, such as those bacteria necessary for the Nitrogen Cycle, to the extent to which Ammonia is available, then Nitrite, and so on.
This also applies to other beneficial bacteria which feed on other by-processes of plant and animal waste products, so on and so forth.
Bacteria act as the purifying agent for the aquarium, it is their primary role to take toxic substances and turn them into live-able waste (of bacteria) products, which are then fed on by other bacteria or plants, etc.
When Bacteria rapidly expand to the maximum limits of the environment, they take up all of the excess available, and will grow to approximately that level.
So an aquarium with aqua soil leaching ammonia, will have an inherently higher level of nitrogen cycle bacteria than another aquarium without aqua soil.
Algae: Algae tend to grow most prolifically in the presence of Ammonium in the water (which is a reason to want to cycle your aquarium as quickly as humanly possible), they also occur when imbalances occur.
For example, BBA will appear when there is a lack of Co2 and an abundance of other nutrients, which the plants cannot grow to support without the proper level of Co2. (Principle #2 is the Law of Minimums, so if there is a lack of Co2 and an abundance of fertilizers, it paves the way for nuisances like BBA, because all available Co2 is used, and there is an excess of other nutrients which are not being used by plants or micro-organisms).
Why Principle #1 is important to algae growth
Algae is like the fruit fly. They are relatively simple organisms and occupy a space on the evolutionary tree somewhere between super-simple micro-organisms and complex plants.
Algae also replicates quickly, invasively, and aggressively.
A small amount of algae on day one, if left alone, could be a massive outbreak by day 3.
Immediate action is required to eliminate these pests before they become huge problems.
This is huge, because The number one reason why people give up, is because of too much algae.
Plants as the example:
The best plants for aquascaping tend to be aquatic weeds. These guys can be pretty invasive and they will strive to cover as much ground, as quickly as possible over all the other competition.
A plant will grow and grow and grow and grow until it cannot grow anymore, even past the point of "healthy" growth, it'll continue to live on with half-dead growth going forward.
Let's evaluate Hair Grass:
spreads via runners and heavy root systems which expand out in straight lines across the substrate. The runners pop up as many hair grass nodes as possible and just keep going before filling in totally.
Hair grasses' strategy for choking out other plants is to have a root system so thick that nothing else can really compete on a root-level for nutrient uptake.
Let's evaluate Glossostigma
Glosso takes a similar approach, it will go up, of course, but it also tries to cover as much ground as possible via runners that go straight out from it's nodes.
Glosso's invasive strategy is to just cover real estate as quickly as possible, and will do so even if it's growing in relatively thinly across the substrate. It'll then double back and start filling in from other runners going in opposite directions. Glosso mainly tries to uptake Co2 and "block" other plants via lots of thin growth in real estate.
HC on the other hand, grows in "zig-zags," it too, tries to cover as much real estate as possible, as quickly as possible, but rather than go wide and thin as quickly as possible, it "mounds" in one spot as quickly as possible while sending out runners that expand the territory inch by inch, which then mound and repeat the pattern.
HC will completely block the growth of other plants by simply making an impenetrable mound fortress. As an experiment, try placing a few sprigs of hair grass in the middle of a mound of HC, and another sprig away from the mound.
The hairgrass away from the mound will spread quickly, while the hairgrass in the mound will slowly die or just stay steady with it's few nodes.
Marsilea is probably the most vulnerable carpet out of the ones listed here.
It will grow out in really really really straight lines across the substrate, unlike glosso it doesn't have a huge tendency to eventually double back. So it just keeps going straight out in one direction. This is a plant that when you start with this and another type you need to just plant a ratio of like 10 to 1 marsilea to other.
Riccia doesn't spread by roots - so it's strategy for take over is to completely and utterly grow as quickly as humanly possible and 'detach,' and populate as many other areas in the aquarium as possible.
It's strategy for winning the nutrient war is pure volume intake of nutrients and, when floating, to block out the light resources of the other plants.
Consequently, because it has no roots, other plants, which grow in with Riccia have a much better chance of survival and rapid growth than others.
These are just a few examples of the Malthusian nature of all of the organisms in the planted aquarium.