Airstone in the Planted Aquarium

The basic theory there is that the co2 you get in your tap is very low and surface agitation will cause the water to absorb co2 from the atmosphere thereby increasing the co2. The airline is simply circulating water but it is also introducing higher co2 levels with that air than you get from your tap. With enough global warming this might work great. At the moment however you just won’t be able to get enough co2 to make the plants happy.

Most of the plants that can handle that don’t need a whole lot of light. So you are pretty much confined to low light plants that don’t grow real fast and a few fish that eat algae, often otocinclus. I have kept tanks like that for years and never feed the otocinclus anything at all. People then add excel which adds carbon and is an algaecide.

If you add more light you end up with algae that is out of control. The only way to really stop that is to add faster growing plants that need more light and more co2.

You have to figure out the balance you can live with. Often I don’t mind cleaning the glass and removing the worst of the sword plant leaves. I am willing to fight the algae in that way. I use java moss to try and remove as much of the nutrients as possible and live with the algae. One watt per gallon is about all that is needed. I don’t keep many fish in those tanks and there are not a whole lot of plants that will grow.