Kalk stirrer VS calcium reactor

[Zante]

Which solution should I go for to keep up calcium levels in my reef? Why?

Reef is 150 gallons with SPS and one (for the moment) LPS

[bertoni]

The calcium reactor can be more stable in terms of the supplementation it provides. Kalk dosing is limited by the evaporation rate, usually, which can change. Also, Kalk by itself often isn't enough. This article might help:

http://www.advancedaquarist.com/2003/2/chemistry