CLR FOR removeing calcium in rad

I was having overheating issues with a nearly new Spectra radiator It had been on the car less than 18 months and was showing signs of being crudded up. As a last resort I used CLR to flush it out, which did the trick and cleaned the radiator HOWEVER it did blow a hole in my heater matrix and I had coolant dripping into the passenger foot well.

Turned out the overheating wasn't due to the radiator after all. On the following test drive it threw the fan belt and a new one (correctly tightened) solved the overheating! Now i just need to swap out the heater matrix but being that the car is a convertible and lives in Florida there's no real rush on that.