Ca Reactor decisions


I have decided to get a Ca reactor. I've been doing A LOT of research and have narrowed my choices to the following:

Either a Reef Octopus dual chamber CR3000D or a GEO C618;

10# C02 tank;

A C02 regulator Electronic Co2 Regulator (with 8 digit LCD Counter)

Which Reactor is better? It seems that most experts suggest a dual chamber, and GEO does not have that.

I have a Neptune Systems Apex controller. Do I still need a separate pH Controller? If so, which is considered the best?

Have I missed anything that I need?


Purveyor of Cool
I have never heard of anybody complain about a Geo.
I have the smaller version of the RO, but it was branded Vertex ... got it at BRS. The pump was a huge POS and I had to swap it before I ever used the reactor. Happy with it otherwise.


I'm in the process of setting up a GEO612 reactor. I've heard nothing but good about GEO but a lot of people like RO too. The dual reactor will reduce excess CO2 from entering you system and reducing pH levels. So if you have pH problems you might want to consider the dual chamber or you can add a second down the road if it is a problem.

You don't need a pH controller if you're using an Apex, just make sure you have the ability to monitor pH with either the full apex or a PM1 module.

What are you using to feed the reactor?


New member
i just pulled the trigger and got a lifereef. rarely do i ever hear of a complaint about a lifereef product