Well sir, I can relay the help offered me on this subject just last week.
I was advised to turn my reactor off and do a good water change. Having done both my alk has dropped 40 ppm in a week. I have been boosting my calcium with an additive. If the calcium level is still up and stable this weekend I plan to turn the reactor back online.
Per Randy the moderator, alk and ca will stay at the same ratios so you must get the CA where you would like it and then the reactor can keep it up and maintain the alk level you desire.
Randy, please correct me if I have given this gent bad info.
Hope this helps.