# Fill or partially fill reactor with bioballs to reduce CO2 bubbles in tank?



## fishstein (Dec 12, 2005)

I modded a 29g Biocube for a freshwater planted tank with Rena XP2 canister filter, quieter fans, CO2 reactor, etc. The reactor I have on this tank is 2 in. diameter clear PVC and is 14.5 inches long and currently has no bioballs in it as I initially was concerned about bioballs a) slowing down flow and b) requiring cleaning once in a blue moon. The reactor has a threaded screw on one end so it can be opened easily for cleaning or inserting bioballs.

I'm getting excellent plant growth with plants pearling like mad. However, I'm getting super fine CO2 bubbles into the tank from the filter outlet, which don't do any harm, but which I prefer not to see in the tank. 

These are definitely CO2 bubbles as the oxygen bubbles are not as fine and larger, and because the oxygen bubbles are larger they rise more quickly, whereas the superfine CO2 bubbles swirl around the water column longer.

A buddy in my local planted tank club suggested bioballs to slow down the flow, and come to think of it, I'm already having to use a strainer over the filter outlet in the back left of the tank to disperse the flow and avoid a fast circular current. Since this is a shrimp-safe fish and invert tank with small residents, strong current isn't desirable.

I happen to have some bioballs I inherited with filters I picked up that I can use - these are about 1 1/4 in. in diameter.

Given the size of the bioballs, you can't get two bioballs side by side in the reactor, so that they are roughly stacked in a spiral stairway pattern.

I thought about filling only half the reactor to moderately slow the flow and keep CO2 bubbles in the reactor, but will it make a lot of noise if I don't fill it all the way? Is it preferable to fill all the way?

It will be mounted inside the cabinet under the tank which helps dampen any noise.

Currently the reactor without bioballs makes no audible noise when the cabinet doors are closed, and only a very gentle noise when you open the doors and get close to it.

I'd sincerely appreciate hearing your experience with bioballs in your reactor.


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## Andy Ritter (Nov 26, 2008)

Hey fishstein,

I use the Aqua Medic CO2 Reactor 1000 on my 75 gallon tank, and it uses bio-balls. I realize that you are saying that you won't be able to place them side-by-side in your reactor, but I don't think that should be an issue. I would fill it all the way with the balls, but even if you choose to go with less, I don't think you will have to deal much with noise. Technically, the one I use is full of the balls, but they aren't actually touching the top of the chamber, so it's not like you have to have them crammed in there tightly so they won't rattle. Mine hangs on the back of my tank, and I can't hear anything. I have cooling fans for the lights and the water that are pretty quiet, but they are noisier than the water flowing through the reactor.

Also, as long as you have the reactor plumbed into the return hose for the tank (after the filter), I don't think you'll have to worry about anything building up on the balls, especially with it mounted in the cabinet. I've only opened mine once in the past year, but that was only because I had taken it off the tank to reroute the hoses, and thought it might be a good idea to clean it while it was off, but it didn't really need it.

Hope this helps.

Andy


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## mids1999 (Feb 22, 2007)

I use a DIY reactor that is made from a 2' section of 2" PVC pipe. (probably very similar to yours just not clear.)

I use an xp3 and I am not getting any co2 past the reactor.
I have the reactor filled with bio-balls. 

I have my reactor plumbed on the return of the xp3 and I have the co2 coming in from the top. The water flows down through the reactor to get back to the tank.

I think it is a combination of the bio balls and the fact that the water flows down through the reactor before going back up to the tank that no co2 gets past.

At first I tried with the bio-balls and the co2 going in at the bottom of the reactor, and I was getting co2 past the bio-balls.

This is on a 75g tank so I am sure that the same setup would easily handle your 29g. Especially with the slower flow rate.


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## Ozone (Sep 30, 2009)

can you post pics of your reactor? mids1999 thanks


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## mids1999 (Feb 22, 2007)

it is behind my tank, so it was hard to photograph.


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## mids1999 (Feb 22, 2007)

Here is a link to where I got the plans from.
http://www.rexgrigg.com/diy-reactor.htm


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## Muirner (Jan 9, 2007)

I built a reactor from 1.25" PVC and i believe it's 12-16" long. I inject on the return side of my XP3 and i find that when i'm getting CO2 into the filter my flow rate is too high. I also have biorings in the reactor. I can dig up pictures if desired. Mine isnt that pretty but at 1 bps i get 30ppm of CO2 in my tank no problem. I've had the same 5lb co2 tank running for about a year and it's still going. This is on a 55gal tank and milwaukee regulator.


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