CO2 Poisoning

This post deals with what I am meaning regarding the gas exchange of co2 from the fish into the surrounding water and mentions that the fish should be able to cope at non excessive levels of co2 (which we can all testify to) and even, to a degree, increase its respiration to increase its o2 intake accordingly, thus I think I have finally grasped the idea of surface agitation while injecting co2.

However, I do still have a niggle that sufficient co2 levels can be achieved without surface agitation thus ensuring fish dont over respirate (is that even a term lmao) and we dont use more co2 than is neccessary?

I mean I am also using the assumption that 30ppm of co2 is quite adequate for planted tanks, if so, I know this can be acheived with quite a high stocking density of lifstock with no detriment to them and without surface agitation, or is 30ppm of co2 seen as more of a minimum target? I know it is all balanced with light levels, fish stock, plant biomass etc, but still, what do you think Flora?