Saw a post about this around the forums. Anyone know any particular guidelines to follow to make sure you're getting proper CO2 injection or do you just need to crank up the CO2 and let it rip? It's in the intake tubing, by the way. I also notice the bubble rate is rather erratic. It's never a reliable bubble count...it might go one, two, one....two...one, one, etc. Any ideas or did I just mess this up horribly? It's plumbed into an Eheim 2215. Also, be very jealous of my makeshift electrical tape CO2 tubing management system.

How are you breaking up the CO2 bubbles and diffusing them? It looks like your just pushing it into the tank without much contact time. Am I missing something here?

It's in the intake tubing of the canister filter (intake, CO2 plumbing, filter, outflow in that order). My understanding was that you could just inject CO2 inline into the filter and the impeller would chop the bubbles up and diffuse them.

You mentioned Cerges so I was looking for a reactor, but if you're pumping directly into the intake you're not using one. To check and see if it's working, get yourself a drop checker and 4dKH solution. If it turns green, it's working.

Edited to avoid confusion. I've seen people directly hook the CO2 tubing into their intake tubing and sealing it with foam/whatever for diffusion so I thought I'd give it a try. Problem is, the solution is staying dark green (shooting for a limey green) even when it should theoretically be working. My thought was that the bubbles would pass through the filter and be diffused by the impeller chopping them up. Terrible assumption and a waste of ~$20 bucks?

using the canister impeller to chop up the bubbles and diffuse CO2 is a horrible method because 1. its inconsistent and 2. its horribly inefficient

make a proper CO2 reactor or get a proper inline diffuser/atomizer

Looks like another trip to the good ol' Home Depot then. Hopefully I can salvage most of the parts used to make a Cerges.

Out of curiosity though, why is this method so inconsistent and inefficient?

you cant control how the impeller chops up bubbles

the bubbles can come out any size

hardly any contact time with water

large bubbles float straight to the top...wasting the majority of the CO2


also, reactors go on the output side of the canister...youll [potentially] airlock your filter

Makes sense. Thanks bud.

Are you getting bubbles in your tank or is the co2 diffused 100% prior to coming out of the outflow. That is how you judge whether it is working or not...

Also, what is your working pressure set up at? Inconsistent bubble rates are usually due to a low working pressure or a bad needle valve.

Didn't notice any bubbles but if I shook the canister it would always make the sound like it's kicking out air then go back to normal. Maybe all of the bubbles were just getting stuck at the top?

For a few months I had my CO2 inject directly into the filter intake line: I just put a Tee on the main 5/8" I.D. tubing. However, without a diffuser the tee tended to build up and discharge large bubbles of gas into the canister. Then the bubbles would collect and every 5-10 minutes the filter would "burp." It would then expel a huge about of CO2 into the tank in one shot . . . most of that gas escaped to the surface and wasn't absorbed.

I eventually ordered a typical CO2 diffuser-airstone-thingy. This setup puts out a mist into the water with much more consistent / efficient results.

(the filter I worked with was a cascade 700.)

Just went ahead and made a Cerges reactor. Works like a champ.

You could use a Magnum 350 filter witch has the motor on the bottom , Filters with motors on top could cause air-locking your filter.

im curious about this.

the increased co2 reaction inside the canister would make the water acidic.

doesnt that hurt the bacteria inside?

Also wouldnt the acidic nature of the water would hurt the oring over time?

lastly... if u were injecting more then 30bpm, couldnt u potentially airlock the canister?