JennM;409239 wrote: A lot of growth also depends on the type of structure the corals take on.
Big D noted that the Red Planet grows out and not up - that's because it's a tabling acro. It will spread outward before it grows upward, that's the nature of the coral. Once it gets wider, it will grow up, somewhat, but it's a shorter grower, and more of a wider one, versus one that grows tall and "leggy".
Caps do grow quickly in my observation, that's also their nature.
If you aren't testing your parameters, it's impossible to say "why" some seem to be growing faster etc., other than what they do normally. If your calcium/magnesium is low, then it's possible that the hardier Caps are taking up more of the resources, and the acros don't have as much "available" to them.
Jenn