Pick up "bubba" Rits Clam when you go over there to test the water it will drop out as soon as you put that beast in the tank if it will fit, Rit you still got that thing?
If CA was really that high it would probably be precipitating out in a "snowstorm".
Something isn't right - have Rit, or I test the water. Probes can lose calibration and if it's an API kit, well I've seen "600" on an API kit, turn out to be 275 on a Seachem kit (with reference solution verified).
And Rit's right - testing for Alk and Mag are a good idea too.