These are links that I have found Usefull
			Everything you want to know about Frogs
				Everything you could ever what to know about Co2 in your Aquarium  part 1
				Everything you could ever what to know about Co2 in your Aquarium  part 2
					external inline co2 reactor
						auto top off system
							The Rex Co2 reactor
								Jello Yeast Reactor
									Co2 reactor
										Co2 info