When 'cycling' a tank is discussed, it typically refers to the process of establishing an adequate bacterial filter in the tank. But, new tanks will cycle through different phases of algae as well. Example would be blooms of diatoms. While GHA doesn't have to be a part of the cycle, it often is, and can go away on its own - or persist as a problem. Without a picture, cannot be sure, but if the algae is turning white it usually means it is dying off, which is a good thing. I would attempt to mechanically remove as much of it as you can though.
