Calcium Questions

I wouldn't be too concerned about your high calcium reading if you are not experiencing any problems! If you stop dosing with purple up or other calcium additives, your calcium level should drop over time due to the consumption of calcium by inverts, and corals especially!
The thing to watch with a high calcium level is the diminished level of magnesium and alkalinity associated with a high calcium reading...
I have a high calcium reading in my tanks, always have and will continue to do so, as I keep my other parameters in check plus with the amount of inverts, stonies and Tridacna's, I have, I feel it is a good thing to ensure their growth and health!