CO2 Generator and Reactor

Here is the set up I use for generating CO2 for amazing plant growth.


This is a storage container that I bought from Walmart around $5.00 if I recall. It has a nice wide mouth, so there is no funnel needed to add your ingredients, and you needn't worry about it tipping over and filling your aquarium with sugar water. It also has a rubber "O" ring to prevent CO2 leakage. In this I put about 1 1/2 cups sugar, about a teaspoon of baking soda, about a teaspoon of protein powder, and about a teaspoon of active dry yeast. Fill about 2/3 with tepid water and mix well. I've used a few different recipes for the sugar mixture and this one seems to work OK. It produces CO2 for about 2 weeks. Feel free to try out different recipes, to see what works for you.
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You can see I've drilled down through the top of the container with a bit the same size as a 3" piece of rigid airline tubing I have heated and bent at a right angle. The top is plastic so it is easy to drill through, and it has two layers, so the rigid tubing cannot be torqued loose. The rigid airline tubing is fed through the hole, (the rigid tubing should not protrude very far into the container, just barely inside is good) and hot glued in place from both sides. To this you can attach your flexible tubing that leads to the aquarium. Always locate this generator above the waterline.
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Here you can see the reactor I use at the other end. The tubing leads down into the aquarium and is connected to a "Hydor Ario 2 Aerator" You can order these online at Petsmart for around $20.00 (I think). This thing really chops up the CO2 into tiny bits! You can place the reactor under or near the outflow of a filter to keep the bubbles in suspension longer, but it is not necessary, because many of the bubbles never even reach the surface anyway. There is a drawback to using these as reactors: plant material can get caught in the impeller. Place this away from Java Moss!
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Another view of the Hydor Aerator
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With proper lighting you should see quite a bit of plant growth in just a few days.
Good luck!
-Thom

I've used a few different recipes for the sugar mixture and this one seems to work OK. It produces CO2 for about 2 weeks. Feel free to try out different recipes, to see what works for you.

What is protein powder?

Edit: It should read What is protein powder adding to the mix?

IDK something called Advant Edge soy protein. I Got it at Walmart too, it is supposed to fuel the yeast. I don't know if that is just wives tale or not. Couldn't hurt I guess. BTW: the baking soda is supposed to slow down/prolong the reaction. Does anyone have any scientific basis for this, or merely anecdotal evidence?

I just looked it up, and the Hydor Ario 2 Aerator is $16.99 and Petsmart.com

The protein powder is used to make energy drinks and can be found in the health food section of the grocery store. Get the cheapest kind they have. It is used to feed the yeast and keeps it going a little longer.

bump

Would this seriously boost the dissolved CO2 any significant level?
I'm a skeptic.

Edited by AndrewAcropora, 18 December 2008 - 01:56 AM.

Would this seriously boost the dissolved CO2 any significant level?
I'm a skeptic.

It would depend on the size of the tank, but the reaction produces CO2 which is then only able to go into the aquarium or pass through the water and dissipate into the air. So there is a boost. I'm doubtful that you'd notice an effect, from a unit of that size, at all on a 100 gallon, but on a 20 gallon it would likely be quite effective. Multiple or larger reactors would likely work well for larger tanks, but I'm sure you'd hit a point where it is more cost/space/maintenance effective to simply buy a pressurized tank driven unit.

It would depend on the size of the tank, but the reaction produces CO2 which is then only able to go into the aquarium or pass through the water and dissipate into the air. So there is a boost. I'm doubtful that you'd notice an effect, from a unit of that size, at all on a 100 gallon, but on a 20 gallon it would likely be quite effective. Multiple or larger reactors would likely work well for larger tanks, but I'm sure you'd hit a point where it is more cost/space/maintenance effective to simply buy a pressurized tank driven unit.

Correct. It has been claimed using a 2 liter bottle for the generator (same amount of ingredients) produces enough CO2 for about a 30 gallon tank, when using other bubble reactor methods. However, I have used this set up for a 75 gallon with good success. Mostly, I think it is a function of the efficiency of the reactor. Many reactors use inverted bells, or bubble counters, or power heads pointed downward with a gravel cleaner attached to the end to suspend the bubbles. The aerator I use for the reactor really pulverizes the CO2 into tiny micro-bubbles so that there is greater contact in the water column. If you place this in front of a filter output, most of the bubbles never even appear to reach the surface. To use this on a 100 gallon tank would probably require two such rigs. Alternating the replacement of the mixture would prevent PH fluctuations. However due to cost concerns, you would probably be better off getting a pressurized CO2 tank system for VLTs (very large tanks). But it is also fun to experiment with this DIY stuff, to see what works and what doesn't.

This low-tech CO2 production method for aquariums is fairly common, you can find information in lots of places throughout the web. This one works for me. I like my method because it won't tip over, the rigid tubing is stable, the reactor really works great, and there is no need for funnels to add the mixture. Look around the web to find one that may work for you. Here's one link to a pretty good explanation for this low-tech CO2 production process:

CO2 HERE


-Thom Ruf

Just FYI, Lowes has a Co2 tank and regulator on sale for $99.00 in the paper today. I've used these on 150 gal tanks in the past and they work well. They're made to hang on your belt and power air tools....Jim

Just FYI, Lowes has a Co2 tank and regulator on sale for $99.00 in the paper today. I've used these on 150 gal tanks in the past and they work well. They're made to hang on your belt and power air tools....Jim

How long do these smaller canisters last?

I have heard that if there is some water movement at the surface, you can lose the CO2 almost as fast as you put it in.

I used the setup described here http://www.qsl.net/w...ria/diyco2.html , I used this setup on a 90G with success, I am going to be setting it up again for another 90G i setup, if I need to later I will go with an actual pressurized system but right now I dont want to spend that much money, plus if I do go with a pressurized system I want a PH controller as well.