Here are the components that I use:
GEO 624 calcium reactor (this reactor is made from top quality acrylic and has some cool features, like a place for the pH probe on top, a drain valve and a very good pump, mine came with a Pan-am, but the smaller ones come with Eheims. I use a large grain media because it is a true reverse flow reactor ( I say "true" because many reactors just push the water through a tube in the middle that lets it flow to the top, GEO has an external tube that pushes the water through the bottom). It also has a very high flow, which basically circulates the water a number of times before it is released as effulent.
http://www.aquariumplants.com/AQUARIUMPLANTS_com_s_Co2_Regulator_The_BEST_p/co2-1.htm
This regulator is top of the line, I've had a couple of the major brands and had problems with them, but this one is built beautifully and most importantly, it works.
AquaController Jr. - This bad boy controls everything on my tank, including the calcium reactor and is probably the best piece of equipment I have (in terms of usefulness). If you are going to control a calcium reactor you might as well buy a controller for the whole tank and hook it up to your reactor.
Pinpoint pH monitor- As my levels of effluent increase with my SPS growth the CO2 in the tank can begin to depress the pH, this simple electronic monitor makes sure that I can easily check my pH levels throughout the day and night to make sure my tank is not dipping too low.
CO2 bottle- Any aluminum bottle will do, as long as its 5lbs or more. I use a 5lb bottle and it doesn't have to be refilled too often, some people prefer a 10lb bottle, but unless you have a 300 gallon SPS tank with high calcium demands it probably isn't going to be necessary.
These products will allow you to use a calcium reactor easily and help you succeed. There are a couple tricks if you don't want to spend the money on all this, just tell me what you don't want to get right away and I will tell you what you can do.
