Okay then. Back when I was a young buck(haha) and dosing Co2 I could never afford the bigger tanks so never worried too much about the 1-2 bubbles per second thing. That's what I used. But now that I have a bigger tank 105g, I'm looking for some kind of info on how much more I should be using and I can't seem to find much of anything relating to Co2 quantity vs. size of tank. What am I missing?
What you need is a drop-checker to monitor the CO2 level in your tank.
The bubble-counter gives you an idea of your supply of CO2 into the tank. This supply may or may-not be sufficient for the plants or even be higher than what the plants can consume. So either the plants will not get all the CO2 they can consume, or CO2 may be at an excess and build-up in the tank threatening your fishes, or you may be lucky enough to be supplying the right amount.
How much CO2 your tank can consume depends on the mass of foliage in your tank (this may vary with trimming and growth), and the type of plants you have there, and also the intensity of your lights, and also again by the plant nutrients available. So you see that it is impossible to predict CO2 consumption/requirement with certainty and the size of the tank is only a very minor variant.
A drop-checker is a in-tank gadget which will let you know if the CO2 you are supplying is building up without being consumed and therefore the supply is threatening your fishes. Its telling you to reduce the CO2 supply. By observation and trimming your CO2 supply; you will soon come to know the exact supply rate your tank needs - and the rate that you should want to see in your bubble counter.
The drop-checker is only a ph indicator in a specific alkaline solution with a captive air head which is connected to the tank water. This air-head has the same equilibrium composition as the gasses in the tank water and there the indicator solution also has the same equilibrium of gasses as the tank water.
Now if CO2 level increases in the tank - then the CO2 level will increase in the captive air above the drop-checker indicator - and also the CO2 level in the indicator solution itself. With the increase of CO2 level in the drop-checker solution - the ph of the solution starts to decrease and the colour of the indicator starts to change. The colour of the indicator will give you the CO2 concentration in the tank, in ppm, from the comparison with the colour chart.
So do get yourself a drop-checker and end your uncertainties.