First off, how did you alk/calcium ratio get so out of wack? If you do regular water changes and dose equal parts of a two part solution, then your calcium and alkalinity should stay close to balanced on their own. At this point, I wouldn't add a bunch of the calcium to try to get the tank balanced again. First off, get your calcium and alkalinity levels checked with a different brand of test kit. Many times, people have bad test kits and they panic over nothing. If the numbers on the second set of tests verify the results from the first set of test, then proceed with the following: Instead, I would do a 2-3, 10%-20% water changes three days apart and test again. The numbers should be much closer to being balanced after that. Once that is done, then you can add a little calcium additive and SLOWLY raise you calcium up.
He's a good article to follow to solve alk/calcium issues.
Chemistry and the Aquarium
For future reference, whenever ANYTHING in your tank seems way out of balance, 10%-20% water changes should always be the first step since they will get your tank closer to being balanced. Once that is done, you can make MINOR water adjustments using additives.