I've been having a heck of a time finding the lighting and CO2 balance in my newest setup. I don't have much of algae problems to speak of, but growth is far from optimal in some plants, primarily those who are poor CO2 competitors, ie rotala macandra green, HC, pogostemon stellatus.
Today I changed the water towards the end of the day and noticed that my ATI light was at 18% power (on its way to OFF) when I finished and I still saw a great deal of pearling...pearling I do not see when the lights are up to their scheduled power of 40%. I know plants pearl very well after a water change, but could this be a clue as to how low I can set my lighting and still get good growth, or is this just a "happy" response from the plants only due to a water change.
I figured I would reduce the lighting further and will be able to back off the Co2, it has been stressing fish. Could I back off to say the 20% level I saw the pearling at after the water change provided I found a good CO2 level? The trimmed stems of the hygrophila pinnatifida were pearling very well at the 18%, the HC like I have not seen except with water changes.
Please share your thoughts on this. Thanks!