I think that depends on what you are keeping. I've not had any I'll effects at 0.5 /day with basic LPS and Monti digitata to get from 6 to 8 in new tanks that are chewing through alk.First thing you should know....raise it slowly! Don't try to go from 6 to your target in one day. 0.1 to 0.2 changes in DKH per day are safe.
I use Fritz RPM
Fritz RPM Calcium Buffer System Pt. 1 Alkalinity
Fritz Aquatics' Fritz RPM Calcium Buffer System Pt. 1 Alkalinity was designed to help aquarists maintain the proper alkalinity and calcium balance.fritzaquatics.com
But you should read this first:
Slow and steady is always a good approach though.