Mix the 2 parts of 2 part before putting in tank?

[cherubfish pair]

Mix the 2 parts of 2 part before putting in tank?

[moo0o]

if in mix as in mix them together (calc and alk), no.

[IPT]

Not only should part A and part B not be mixed together before adding, be sure you add them at different times or even different parts of your system. I add my Part B to the sump and part A to the tank. This basically elimnates the chance of them mixing and precipitating out of solution before it gets dispersed in the tank water (which means they would then by useless to the coral).

[Randy Holmes-Farley]

They also cannot be combined into top off water or even water change water unless the amounts are very small. The problem is that calcium carbonate will precipitate and not redissolve when added to the tank, taking away the benefit.