I'm fairly new to LPS (well, reefkeeping in general), but so far mine are growing quite nicely. I use IO, but I also dose with kalk and B-Ionic 2-part to keep the calcium around 400. I also add 60ml of ESV Magnesium about once a week. Remember that both magnesium and alkalinity are important to the calcification process, though I can never remember all the details of the interplay between these three elements.