Quote:
Originally Posted by ceg4048
I'm not sure what the answer is but it doesn't seem reasonable at all to me that CO2 concentration is lower at the top of the tank. It's the lower regions of the tank that suffer BBA most frequently and in deep tanks it's the carpet plants that appear to be most limited. Any CO2 mist or bubbles tend to rise as they exit the injector so it seems to me that if anything, it's the upper regions which would tend to have a higher concentration. It also seems that if a fish gulps a bubble of air and passes it over the gills, that air bubble would tend to have a lower CO2 concentration than it's blood facilitating the osmosis of the CO2 from blood to bubble. I suppose it could be crudely tested by stacking an array of drop checkers vertically and observing the color change profile of each.
Cheers,
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Makes sense about the fish gasping for air bubbles. I'm not sure whether fish are just hanging out near the surface or taking in bubbles, I've never had a co2 overdose before to observe what actually happens.
It's true that co2 bubbles rise, but what we are measuring are not the visible bubbles, it's the concentration of dissolved co2. Just because bubbles rise doesn't mean that co2 concentrations would be higher nearer the top. The bubbles usually start off larger at the bottom and by the time the get to the top, they have shrunk in size, meaning they have mostly dissolved, having left behind most of their co2 before they even get to the top.