I completely disagree with the opinion that you don't need to supplement. While it is true that regular water changes with high quality salt will provide ample nutrients/supplementation, I always recommend to routinely dose Calcium, Phyto, Iodide, and Strontium & Molybdenum. This is because as you add more corals and as your corals grow over time, they will require more elements than what your water changes will provide. Also, you don't want to ever be deficient in any of the above. Better safe than sorry. If you want your corals to really grow, your levels of these elements need to be high. They will absorb them regularly, so make sure you always have the right amount for them to do so. I have 50+ corals in my 125g tank and they all are flourishing because I regularly dose the above supplements.