Dutchstyle

To put it briefly. For a beautiful plant aquarium with small fish you only need 5cm high sandy substrate (1mm diameter). Normal light. Ready. Shocked. I tested it. Don't worry, there is enough Co2, NPK and Co. available. Every living space is warm enough as well. Except for discus and cichlids, they don't need filters. More than 50 percent of the filter capacity is taken over by the biofilms in the aquarium. The substrate is oxygen-free and reduces substances to plant nutrients.

For a beautiful plant aquarium you do not need any water changes, fertilizers or any filters. The plants in most aquariums have no chance to grow at all, because they do not have any nutrients. ...Every normal filter works oxidatively and converts the ammonium into nitrate in a short time. But plants need ammonium. The filter manufacturers don't know this. Water changes remove nutrients from the plants, provide excess oxygen and remove the humic substances that protect the fish (also present in Lake Tanganyika and Lake Malawi, but not as much). If there is an excess of oxygen (too much light or strong water changes), the plant is stressed and almost suffocates from it. You can see it in the oxygen filaments). Normally, the oxygen dissolves in the water immediately.