Some of the colonies are quite old and came from a previous tank. For example the Oregon Tortuosa, which is the big blue colony on the left, I've had for over 5 years and started as a half inch frag, but I would contrast that with the purple tree shaped coral on the bottom left which I got as a brown frag two years ago and which I trim back on an almost daily basis. The majority of the colonies are around the 2 year old mark on average, and the variation in growth is almost unbelievable as some barely grow and others are virtual weeds, oddly enough or perhaps not so oddly, the corals that are the "hottest" are the slowest of growers.
No . . . no dosing. Big believer in the Berlin Method. In fact I'm starting to think that my 400 lbs of LR are the real secret here given the most recent research showing how little skimmers actually do to clean the water.