CO2 aquarium reactor

thingiverse

I am running several fish tanks that are fertilized with CO2. The main issue with glass diffusers is that a lot of the CO2 is lost when it's introduced into the aquarium. Bubbles rise to the top and evaporate into the room. One of my 700-liter tanks was consuming a 2-kilogram bottle of CO2 in no time. My tanks are equipped with HMFs (Hamburger mat filters) and a simple pump behind them. I tried using glass diffusers under the pump, but the pump is noisy when it's filled with air. So I thought about replacing the diffuser with an inline reactor instead. The concept began with a connector for the outlet tube, and then evolved into a small tank filled with Siporax. The design is simple and effective: water flows from the pump (300 liters per hour) onto top left of the reactor, and CO2 enters from the bottom. The CO2 tube is positioned halfway or more to the top, preventing any leaks I've observed with previous prototypes. Water passes through, and CO2 is absorbed at a rapid rate. You can hardly see any bubbles on the outlet, which is suitable for the 150mm version. I'm printing a 200mm version to see if it improves, and if not, I'll create a modular system. The water then flows into the inner tube to the top and exits on the right. This design allows you to install it inline with any 16/22 tube without having to fiddle with tubes excessively. In my case, the pump had a 12/16mm connector that fits nicely into the larger tube. The reactor is fully submerged, as I always use transparent clear PETG (you should too). I'm impressed that the print (two perimeters, four top/bottom layers with a 0.4mm nozzle) is airtight. Further updates may follow.