Just make sure you are keeping track of your alk aswell. It can creep up there when you are dosing kalk and running a CA reactor. Jay have you considered adding a second chamber to your ca reactor. You run your effluent through it after it comes out of the first chamber and it gives the co2 more time to diffuse. Less co2 = higher ph. This will help keep your ph higher without having to up the kalk dosing.