i am downsizing to new tank cycle has been going for six weeks, no algea breakouts at all. i am gonna use exsiting rock from a larger tank i have had for 9 months, this tank never did so well but did have a bit of the green blue, almost black algea on wall and powerheads. couldnt ever get rid of but never was a nuisance. if i transfer rock over to new tank will the propblem keep reaccuring.