Percipitation of the calcium aka 'snowstorm' in the tank is possible with Ca
levels that are 'too high'. Running high Ca
lends to faster depletion of Alk
and a closer eye should be kept on Mg
levels. Running elevated levels of Ca
can also damage your pumps and acrylic devices like protein skimmers. I can attest from personal experience, getting the Ca
deposites off of your equipment is a long vapid process. However, what is 'too high' is a subjective discussion and depends on each reef keepers setup and stock.