swell setup , like you I have not had very good luck with hairgrass even in good lighting and co2. My chain sword has pretty much covered it all anyway.
Keep the posting updates :grinyes:
I have no problems with hairgrass as you can see if you look at my fish stuff (in sig). In both my 90 and 75 gallon tanks I have between 1 and 1-1/2 wpg with Co2 and it thrives. I wanted to see just how much lighting is actually needed to grow it. It seems to live ok but definately doesn't thrive with only about 3/4 wpg and no ferts. The hairgrass was also taken out of the other tanks and had good roots to begin with. I don't think it would ever even survive if just planted from the pot.