I have a buddy with 29gal that he otherwise neglects (adds no nutrients)except for frequent and massive water changes. The bottom 1/3 of the tank, including glass/powerheads and anything moving slower than a crab, is a solid mass of pink, and it's taken only a few months to get that way. He's given up trying to clean it off, but has backed off water changes to keep from feeding it.
Nothing is prettier on rocks, IMHO
, than coralline that's grown so thick it looks like thick, polished plastic. I try to keep it at a moderate pace in my current 55, and have a few splotches of the slower growing and rarer tan and green types growing on a couple of my rocks.
or salinity will slow it down.