Aquarium DIY CO2 Generator System Kit, G200

Ok, this CO2 Generator System kit is intended for a citric acid setup. Guess what? It works for yeast too. One caveat with yeast vs. citric acid... If you let the pressure build up on yeast, the mixture's CO2 content will increase and the pH will drop. You can potentially shut down the fermentation through pH drop and CO2 toxicity, although the yeast will likely just go dormant vs. dying. What this means is that shutting off the white on/off valve to build up pressure is unlikely to produce enough pressure that your gauge will show anything at all. Even with this, you can build up enough pressure inside the generator bottle that you can use the regulator. I use a Paffrath bell to regulate the amount of CO2 in surface contact with my aquarium's water. This is probably a better idea than using a CO2 fine-mist diffuser for yeast, since you have less control over production volume and it's better to waste a little bit of CO2 than to overdose your tank. What I like: - Tight seals on both bottle caps and hose fittings. - I like the high-quality appearance. - No messing with silicone and adaptor fittings, this thing just goes together. - Use whatever size bottles make sense as long as they fit standard-sized caps. I use a 2 liter for the yeast generator and a 1 liter for the bubble counter. - No durability issues so far with any hose or fitting failures. - I can position the whole assembly behind my micro-tank without worrying about appearance.

The kit works great only bad thing is the valve that comes with the system, if you let your pressures get above 1.5~ adjusting bubble rate becomes a real challenge. I have come home to dangerously high co2 levels 2 times because of the valve although I shouldn't have left the system generating co2 while I was gone so you could attribute that to user error. Great bang for your buck and my plants are thriving thanks to this kit.

So this device works as planned and all the valves and connections are worth the cost. With that being said they say to use 1 bottle of an acidic mixture and 1 bottle of a base. The acid drips into the base causing co2 to be released. The problem, even with the needle valve turned way down it still goes through a bottle of acid daily. A bag of citric acid will make 2 bottles and is $15, you do the math. Tried cheaper alternatives for acid like just using vinager and the reaction wasn't enough to build pressure and didn't last long at all. As an alternative if you ferment some sugar water with yeast in bottle 1, allow it to bubble into water in bottle 2 (1 way air valve) and it builds around the same pressure and will last for weeks on pennies worth of materials. As the yeast eats the sugars turning them to alcohol, the byproduct is co2. I like to let the alcohol then sit out and sour to vinager and use it for cleaning, no waste.

I tried making my own setup and it wouldn’t hold pressure so I picked this up. I wish I knew about this product in the beginning because it works so awesome! I use it with yeast and sugar and get great results

This kit requires nearly daily maintenance. Initially, I expected to refill the baking soda and citric acid only every other week. However, regular water replacement is also necessary. The water is transferred from one bottle to another via a slow but steady siphon process. With a 1L bottle (4 qt) filled halfway, one bottle empties after a day while the other fills up. Exercise caution when replacing the water. The bottles are highly pressurized, and there is no release valve. To safely open the bottles, you need to remove the diffuser and release the CO2 before unscrewing the caps. I once made the mistake of loosening the cap slightly to release the pressure, which caused the cap to pop off and water to splash out. The water, after reacting, becomes sticky like syrup, resulting in a considerable mess. Although the chemical product is low in acidity and food-safe, it still makes me anxious each time. Additionally, since the two bottles are attached, the entire setup is physically unstable. If the bottles fall, liquid can enter the gas outlet pipe, flow directly to the diffuser, and potentially reach the pressure gauge as well. This risk is particularly high when changing the water or refilling the reactants. The kit includes a magnet to stop the reaction by moving the pipe away from the reactants. However, this needs to be done twice a day, which can be inconvenient. Overall, the solution is not sustainable in the long term.

Works great, directions aren't too awful clear, but once you watch a few YouTube videos, you'll understand the directions.

Great alternative to the diy yeast system. Has kept great pressure for 3 weeks so far. The valve is a little aggravating to get the flow adjusted. May look into adding a solenoid.

The two-bottle CO2 reactors suck. They're prone to clogging the line with baking soda, the valves are of poor quality and hard to modulate just right, and always seem to release CO2 in massive surges no matter how I adjust the primary and needle valve; I've tried the ball valve wide open and the needle valve to regulate by itself, I've tried just cracking the ball valve to assist the needle valve with regulation, trying to target 4-8 bubbles per second for my 4x3x6 grow tent (my setup is bottle output -> solenoid -> ball valve -> needle valve -> hose to tent -> bubble meter -> diffuser in jar of water), and it is very inconsistent. I've tried purging all the lines with air, added a solenoid valve to run off a timer in tandem with my grow lights, so the valves can be set in place essentially calibrating the system so when I refill I don't touch the valves at all... all to no avail - sometimes the acid is consumed in a day or less, and sometimes it will last a week or more. The system just plain sucks - and yes, I've verified there are no gas leaks. The valves in this kit are just a really poor choice for this application. Great concept, but really lousy implementation. I'm taking this system and tossing it in favor of a stainless steel bottle reactor that uses a single bottle with a proper pressure regulator and high-quality needle valve. I suppose the best I can say about this is that this review can save you wasting money on an unreliable solution. :D