I agree with all that's been said. There are pros and cons of both systems. I'd just like to clarify one thing. My calcium reactor does not affect my pH at all. I track my pH with a controller and there is no noticeable difference between when it is running vs. when it is not. I know others have raised this concern, but for me it has been a non issue.

- Brad

switched from a reactor to doser and though both were set and forgot, the dosing pump is easier.

about the only thing I've seen of a reactor being better is they'll add trace elements (since media is crushed coral) and cheaper overall with large systems (here).