These days modern aquascapes are beautiful but lasts around 1.5 - 2 years. Soils get depleted and you need to replace it or add root tabs, not mentioning fertilizers weekly or daily and of course CO2 injection... In fact it is not that laborious but...

My dream was always to create a self sufficient ecosystem in aquarium.
By that I mean aquarium that would lasts like 10-15 years or more without any fertilization nor CO2 injection.

Why?
As I said injection CO2 and fertilizing regurarly is not that laborious or expensive but Im quite often away from house for quite long period of time... another thing is that I think is such a pitty when you invest so much time and effort to aquascape that would last only 1.5 - 2 years and then you have to start over again or do massive task like replacing old substrate...

My idea is to use obviously plants that are not that demanding in CO2 or nutrients and provide them nutrients from fish waste (phospate and nitrogen) magnesium and calcium is in my tap water, but problem will be with potassium, iron and trace elements.

My idea is to use potassium feldspar like microcline or orthoclas or to use greensand (commercial product mined from bedseas containing glauconite) maybe fine crushed in to sand as a long 10+ years source of potassium. I hope there is a way / process that plants are able to extract slowly the potassium from the mineral because I guess it is not in soluable form...

Iron is another issue... my idea for long term source of iron would be Laterite or red clay...

For long term trace minerals I have no idea... but greensand acutally contains some trace minerals, so maybe that...

What do you think? Is it actually possible to create a beautiful aquascape with basic hardy easy plants and keep the aquarium for that long time with no CO2 and no ferts?

What do you think about my ideas - using feldspars, greensand... is there any way plants can get the potassium, iron, trace from it? Is there any way that these sources will last that long as I wish?

Your dream has been shared by many. You may be interested in getting Diana Walstad's book Ecology of the Planted Aquarium. It goes through various aquatic studies while advocating for dirt tanks capped with an inert substrate. She does not use ferts in these tanks but instead advocates using only fish food. Dirt apparently has enough iron in it to last for decades.

No idea how your plan would work but it's probably more complicated than it needs to be with dirt substrate tanks being a viable alternative.

Regarding high tech tanks with soil crashing. It can happen but if you dose the right ferts the aquasoils (or dirt) should take those ferts in and store them and rerelease them to the plants in this way they last forever. The bigger issue for aquasoils is they break down turning into mud over time. If capped then that would not matter.

Inert substrates are also an option but again require ferts. If you don't want to dose ferts ever than using substrate with high cec such as dirt, or aquasoils, and then dose fish food. But of course you need easy growing plants.

Granitic Gneiss seems like a interesting mineral that might be worth experimenting with.

“The minerals are arranged into layers that appear as bands in cross section.[2] The appearance of layers, called 'compositional banding', occurs because the layers, or bands, are of different composition. The darker bands have relatively more mafic minerals (those containing more magnesium and iron). The lighter bands contain relatively more felsic minerals (silicate minerals, containing more of the lighter elements, such as silicon, oxygen, aluminium, sodium, and potassium).”

Guys thank you very much for your time and advices!

Finally I got the book from Diana Walstad, so it helped quite a lot but it still didnt have all the answers. Anyway from what I have understood two options looks quite practical to me or at least worth trying...

1. using Safe T-sorb (high CEC) + laterite + greensand + decorative gravel on sides and top
2. using aquasoil (more practical than dirt) + decorative gravel on sides and top

As a ferts, fishfood will be used, but I have to figure out what kind of fishfood have all the nutrients and calculate the values etc. ...

My another issue is the CO2... Obviously I will use low-tech plants, but they still need some... In the book she describes CO2 releasing from decomposition of organic matter in the dirt, but eventually this CO2 will also be depleted in couple of months.

Do you have any thoughts and ideas about adding regular sources of CO2 supply, organic matter to substrate n.1 or to substrate n.2 that I described?

My last question is about the plants:

These plants will occupy maximum volume of the aquarium - fast growing plants for aquarium stability. I will decide between these three and use only one species so no other fast growing plants will not compete against this main stability aspect of the aquarium:

1. Rotala Rotundifolia / Hygrophilla Difformis / Vallisneria Spiralis

These plants will occupy medium volume of the aquarium - slower growing plants for just supporting aquarium stability:

2. Bolbitis Heudelotii
3. Cryptocoryne Wendtii
7. Hydrocotyle Tripartita

These plants are addition - quite slow growing to add detail:

4. Anubias Barteri var Nana „Petite“
5. Bucephalandra Wavy Green
6. Hygrophila Pinnafitida

Mosses - slow growing to add detail (attached on driftwood):

8. Riccardia chamedryfolia - Riccardia moss
9. Pilotrichaceae sp. - Pilo moss

What do you think about plants list? Im worrying about fast growing plants that are meant to be the stability aspect of the aquarium - that they will slowly dissapear over time, because there will be no regular source of (even low) CO2.

I've been looking into this recently. I'm trying to make a sealed ecosystem to the thought process is similar. Im keeping a journal in that section. Cant link it now I'm on my phone.

I can recommend muscovite and biotite (I think that's how you spell them). They are a kind of mica with lots of potassium. Although, it is unclear to me how this potassium is released.

You probably dont need a long term source of phosphate like I would in a sealed system but if you are a good one is colloidal also called soft rock phosphate. 3% immediately available the rest released over 3 to 5 years.

I'll be following this thread it could be useful to me

There is CO2 in the air, by promoting gas exchange, increasing/aerating water surface you are promoting the exchange of O2 and CO2 from the water.



https://eesc.columbia.edu/courses/ee...e/table_1.html






Plus during the night plants do not consume (significant) CO2 since there is litte light to perform photosynthesis, but still consume O2. This is why people usually don't run CO2 at night.

getting more complex with plants becomes the carbonate cycle (KH) and uptake requirements, etc.



[/QUOTE]As a ferts, fishfood will be used, but I have to figure out what kind of fishfood have all the nutrients and calculate the values etc. ... [/QUOTE]


This may not be as easy as X in and X out.


Meaning minerals/nutrients "IN" doesn't mean that it will be available for your plants. Its complicated, but simply a fish may eat fish food, need 30% of calcium for bone growth and excrete the remaining 70%. That 30% of calcium is unavailable to the fish tank until the fish dies and you left it in the water to decay. Now multiply that by each animal in the tank calculating growth... complicated, right.

Thats why testing and dosing is so popular.

I like the green sand Idea, I will be stealing that for my tank Thanks.
Hope that helps alittle.

Thanks for pointing IN & OUT thing. Do you think that greensand/granitic gneiss/feldspars will eventually release the nutrients even if they are not solulable? Can somebody explain me this process?