On the Seachem products (which are very good) if you are using the calcium additives then to balance the calcium & Alk you must use the Reef Builder as a equal. These two additives are Seachem's version of a 1-2 system like B- ionics.
I now use a Kalkreactor and B-ionics because I have a huge calcium demand in my tank. I have found (IMO) this system is easy and keeps my calcium at 430 to 450, alk at 11 to 12 and ph right at 8.3. I add nothing else to my tank.
Jim