[amoreira]

Cost of a Reactor:

Fixed Cost (initial equipment): $400 for the reactor + $150 for CO2 regulator (I use a beverage supplier to get the CO2 + tank).

Variable Cost: ~$50/year for the CO2 and $40 per year for the media.

Advantages of CO2 reactor:

1) After initial set-up, it's very low maintenance... Every 3 months I put in new media. Every 8 months, I call up the beverage supplier and swap out the 20 lb CO2 container.

2) Keeps alk and calcium levels balanced and stable.

3) Aragonite media contains trace elements, strontium, magnesium etc. that your corals need and at the right ratios.

4) Fancy looking set-up that you can use to impress your friends/chicks etc..

Disadvantages:

1) Initial setup can be tricky. Getting the water drip and CO2 injection rates right does require some trial and error (but so does 2 part dosing). That been said, CO2 reactors tend to give you a balanced/stable water chemistry, once set up and in steady state.

1) Media may be a source of phosphates. This is nothing GFO couldn't clean up.

2) Overdosing CO2 can cause algal bloom and pH to drop. I don't control CO2 dosing with a pH meter on the outlet of the reactor, but use a timer (9 minutes of CO2 dosing every hour). This prevents CO2 overdosing because of pH meter failure. The pH in my tank is very stable and swings between 8.1 and 8.3. I've personally never had any pH issues because of the CO2 reactor. Good lighting and a kick-rear skimmer with compensate for any pH reduction due to a properly set up skimmer.

3) Low drip rate of water through the reactor can be difficult to control. The biggest success I've had with this is using a slip stream from the outlet of my circulation pump (i.e. the pump that pumps water back to the display tank from the sump). Plugging of this flow leads to overdosing CO2 into the reactor and the media can turn to mush if this is allowed to continue for a lengthy period. I've used powerhead type pumps and have had problems with them eventually leaking current (although they're just as effective as using a slip stream). I've used Aqua Medic dosing pump and the Oscar aqua lifter pump and found neither have enough oomph and often plugged. The slip stream method worked best and I eliminated another source of current leakage in my tank.