Korallin Calcium ReactorsKorallin C-1502 Calcium Reactor Package includes; C-1502 Calcium Reactor, Dual Guage CO2 Regulator Deluxe, 5 lb. CO2 Cylinder (Empty) and CaribSea 8 lbs Reactor Media.The already best-selling Kalkreaktor (Calcium Reactor) in Germany has become even better. It completely replaces Kalkwasser, 1 or 2-part Calcium / Buffer powder & liquid dosing. The new and improved Korallin kalkreaktor allows a simple, elegant and high efficiency production of calcium hydrogen carbonate including the necessary balanced carbonic acid. Sit back and watch your aquarium`s pH and dKH being kept at optimum levels. Together with our reliable CO2 System, this is the most maintenance-free Kalkreaktor setup in the world.Ca2+ + 2HCO3 = Ca(HCO3)2 = CaCO3 + H2CO3 Calcium + Hydrogen Carbonate =Calcium Hydrogen Carbonate = Calcium Carbonate + Carbonic AcidA Kalkreaktor setup (ie: one with CO2 System and CaCO3 media) is expensive only at the beginning. You save money in the long term because a 5-pound CO2 refill ($12) lasts you 1.5 years on our Kalkreaktor (and only ours) while a 7-kg CaCO3 media ($42 and good enough for 2 refills) lasts you up to 1 year! And no more tedious daily Calcium dosing. A pH Controller is not required for our Kalkreaktor because there is no chance for the excessive CO2 to escape into your system like ALL other brands on the market. A pH Monitor is a nice equipment to have for fast pH measuring. Though pH Test Kit and pH Pen-monitor can still be used for this purpose.The internal recirculation flow rate of the C-1502 is around 80 g/h. Since that this is a pressurized Kalkreaktor, the dissolution of the media by the carbonized water is enhanced. The effluent rate is only about 0.25 g/h at 40 drops / min. Thus explaining the efficient CO2 & media use. CO2 is being introduced into the Eheim powerhead direct - this is the most efficient Aspirating-Venturi method.