Underground Co2 Injection?

[flyhockey1037]

Has anyone ever heard/seen/considered using the diy soda bottle method for producing co2 and then running line to a gang valve in the substrate of your tank with line running underground to airstones that are placed underneath plants or groups of plants? would this be an effective means of diffusing the co2 into the water? It seems it would be the least intrusive method of injecting co2 (only one airline running into the tank) and also the most efficient since it is injected right underneath the plants and must diffuse through the substrate. Would injecting a small amount of oxygen (air) through an air pump (connected to a valve) underground also be healthy for the plants at nightime?

 

[George Farmer]

I think the CO2 bubbles would quickly shoot to the surface, without the contact time to be able to diffuse effectively. If the CO2 did dissolve in the substrate I'm not sure of the consequence on the substrate itself. The carbonic acid produced may be dertimental to the substrate material, particularly if it were standard gravel due to the lime content reacting.

Pumping air through the substrate is a bad idea I would say. It may oxidise valuable nutrients and prevent the essential build-up of some anaerobic bacteria, responsible for converting nutrients into useable forms for the plant's roots.

Interesting idea though.