11ppm CO2 is quite low if you can get it up a but that wouldn't be a bad thing, aim for 25-30ish ppm. For pearling you need 30ppm Co2 and high light over 2WPG.
Sam
Thanks Sam, I have read a few other posts (and started a new because I forgot to check this one

)and think that the Co2 is indeed the issue.
I have plonked the Bio canister by the lighting contollers (for warmth) which has sped up the bubble rate (which will shorten its life span

) and I am trying to get a second canister, so hopefully that should increase the Co2.
I will get Pressurised Co2 eventually, but I have already spent a bomb on this and with the wife on maternity leave till August (and of course a 3 month old son to look out for) its none to politic to buy more (crap) as she calls it

esp as I have just taken up golf clubs and all.
Thanks for your help mate.