It probably wouldn't hurt to soak the plant in a dilute solution
of calcium nitrate or calcium chloride. That would help draw out any
accumulated salts, and impart some known concentration of calcium.

Several years ago, I had some ICP tests done on orchid media
recovered from flasks with cattleyas suffering leaf-tip necrosis that was
characteristic of calcium deficiency. I don't have the values handy just
right now, but I recall the calcium levels were in the high-double digit
or very low triple digit parts per million level, and the cattleys were
showing the "terminal" signs of calcium deficiency.

The address in the header is bogus. Send no email there.

-AJHicks
Chandler, AZ