Rydr119

It is a big toss up really. Here are some facts to consider.
In the long run reactors are cheaper, compared to dosing.
Dosing you have complete control over how much CA, Alk, and mag you add to the tank.
Ca reactors run for 6 months without needing to be touched where reactors need more solution every week or so depending on resivor size.

With these things to consider I went with the ca reactor.

yeah in the long run a calcium reactor is cheaper but the initial is way higher. If your able to fork out the money i would do the aquariumplants.com regulator will make it easier to dial in and is loads more reliable. If you dose you might concider a dosing pump. Bubble magus just released there programmable doser to make your everyday dosing easier. theres a lot you can do with both. You really cant say one is better then the other. Ive seem some awesome 180+ gallon tanks on the dosing method and in turn ive also seen great tanks running reactors. it boils down to initial cost are you able to purchase the equipment that is needed to run a reactor right. Do you want to have to make more calcium mag and alk everytime it runs low. But one thing that will be the same on both will be the dialing in process. daily testing and tweaking the setup.

I have a calcium reactor that I bought before I even set up my current tank, I just never hooked it up. I don't know how to set it up or dial it in for that matter. I'll have to pull it out of the closet and see what kind it is and if I have all the necessary parts.

Marc has a full write up on setting up a calcium reactor on his melevsreef.com. The write up also talks about how calcium reactors work and how to dial them in.

Automation is cool.