Quit worrying about the CO2.
I would tend to agree with this. While you can play around with carbon dioxide and precisely dose out the right amount of fertiliser -- you don't have to! The biggest myth in the freshwater hobby right now is that the high-tech Amano route is the only way to create a successful planted aquarium. It is not.
The most important thing to remember is that practically all aquarium plants are weeds. In other words, short-lived, fast-growing opportunistic plants that occupy the same sorts of niches as dandelions and brambles do on land. They may well have preferences, but they're mostly adaptable enough to put up with a range of conditions if they have to. The single biggest reason people fail with plants is insufficient light. Get that right, and you're 90% of the way there. The rest is icing on the cake.
If you're having trouble with plants, look at lighting first. Almost always, the default lighting in all-in-one aquaria is too weak, so adding a tube or two to the hood will make a big difference. Another mistake is to start off with plants ill-suited to your aquarium conditions. Like fish, some plants like hard water and some prefer soft.
Vallisneria for example tends to do badly in soft water. Few plants appreciate very soft water. Many plants are coldwater rather than tropical species, so that's another consideration.
The quality of the substrate is endlessly debated, but in practice you can get good results from either a rich substrate or a poor one. Like
OldMan47 I tend to go with the pond soil/sand combination simply because it's reliable, cheap, and easy to pull together using stuff I can get from the garden centre in my home town. But plain gravel can work, though you will need to use fertilisers on a periodic basis to make up the difference, either added to the gravel or the water. Fish waste will provide some nitrate and phosphate, and ammonia is used directly by the fish. But you will need to add a fertiliser than provides trace elements like iron and magnesium.
By far the simplest approach is to combine floating plants with epiphytes. Floating Indian fern and Amazon frogbit provide hiding places and shade for surface dwellers like killifish, livebearers and halfbeaks. They somehow limit algae as well. Epiphytes are things that grown attached to wood, so obviously they couldn't care less about the substrate.
Anubias barteri, Java fern and Java moss are the "big three" species in this class, though there are some others. These are slow-growing, long-lived plants that provide instant greenery. Buy them pre-attached to bogwood and you can arrange them however you want, immediately creating hiding places for cichlids, loaches and catfish. Since floating plants get their CO2 from the air, and epiphytes grow so slowly they don't need additional CO2, you have a nice mix of plants that don't need CO2 fertilisations any more than they need fancy substrates. What could be better?
Cheers, Neale
! None of my tanks have been touched in like 2 weeks except feeding the fish. My high tech tanks look horrible right now, these tanks are pretty dependent on ferts and weekly 50% water changes and trimming. The plants have been killing each other this last week. A big mat of them on the surface blocking out all the light. I literally got to push plants out of the way to make a spot where the fish can eat. My one low tech tank that sees no ferts and no CO2 looks totally fine.
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