I'll rely on my own experience. My 75 was set up for over 3 years and there was hardly a speck of coralline on the glass. My 46 was set up for about 4 months longer, and had 3 walls covered in coralline and I constantly needed to scrape the front glass. I recently broke down both tanks, cleaned and sold them. The 75 had no coralline and needed no cleaning, other than fresh water and a cloth. The 46 required a long soak with vinegar and a razor blade and lots of elbow grease.
The 75 was set up with much more live rock, but none of it had coralline growing on it. The 46 was set up with rock that was covered in coralline. The coralline covered rock originally came from a 29, that I seeded with coralline from another local hobbyists tank.
Both tanks were kept well balanced with similar Ca, Alk, Mg levels.
Another distinct difference is that the 75 was predominately SPS, with several clams. The 46 had no SPS, no clams but quite a bit of LPS.
I'm sure the type of corals kept in each tank had a significant effect on coralline growth, but I also believe the lack of coralline seeded in the 75 had an effect as well.
I'm not at all saying that seeding is required all the time. But I also don't think it's uncommon for seeding to be needed, to get a start growing. Even if not needed, seeding with healthy coralline, will give it a much quicker start, as I experienced in our recently set up 200.
