Depends on your light, ferts, temp etc, in lower temps it grows slower, where as in higher temps i have not had any luck what so ever growing it.
It seams to do best at 24 to 26'C.
In my low tech tank in 1wpg, 26'C and 5ml or seachem complete a week, it doubled in in size in a month, just as a guide, but as i say it will differ from tank to tank.
Simon.
