# Mini CO2 reactor in an Aquaclear HOB filter v1.3b (shown on a Fluval Edge)



## Possmo (Mar 15, 2010)

Brilliant! Did it as soon as I read it. Took about 90 seconds. Thanks for the idea.


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## GlassCat594 (Mar 20, 2009)

nice job.


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## TLE041 (Jan 16, 2010)

Awesome thread, tuonor. Well done!

I've been injecting my CO2 into the AC20's intake for a while now, but the only thing missing is the chopstick. Will DIY generate enough pressure for this to work?


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## tuonor (Nov 26, 2009)

Thanks *GlassCat594* and *Possmo*.



TLE041 said:


> Awesome thread, tuonor. Well done!
> 
> I've been injecting my CO2 into the AC20's intake for a while now, but the only thing missing is the chopstick. Will DIY generate enough pressure for this to work?


Based on other posts, you should have enough pressure to push CO2 through a chopstick with DIY.


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## TLE041 (Jan 16, 2010)

I'll give it a try. The champagne yeast I've started using has been generating a ton of pressure. I'll report back on how it goes.

Thanks again for the guide.


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## tuonor (Nov 26, 2009)

*Stage II modification:*

Was looking for ways to improve the diffusion rate of the system without upping the bubble count so decided to give the ADA "ball glass" diffuser a try. 









This piece is different from other ADA diffusers in that the bubbles are not emitted directionally but rather radiate uniformly from a point source. For this purpose it fits perfectly: its a nudge over 4" long (long enough to stick out of the top of the filter) and the ball is maybe 3/8 in diameter (small enough to fit under the impeller cover).









Essentially, we're just replacing the chopstick from the prior post with the ball glass. However, the diameter of the glass stem on the Ball Glass diffuser is larger than the hole we were using before. So it needs to be drilled / reamed out. Since I was getting out the drill anyway, I decided to relocate the hole to increase the water contact time. Here you can see the hole I drilled near the lower left edge of the impeller cover. Drill a small hole then test fit the glass stem and drill again (I actually drilled the hole a tad too large). If you don't have a drill I'm pretty sure you could ream this out with an Exacto knife as the plastic is very soft. 









This is what the impeller cover looks like with the ball glass inserted:









It just clears the vertical space:









Snap it back in and fire up the HOB.


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## tuonor (Nov 26, 2009)

Does it work any better? Well, my HC pearls more consistently which is positive but the finer bubbles produced by the ceramic diffuser find their way through the filter more easily too (ie contributing to some fizz in the water).

Going to try to run more concrete tests (probably time versus pH) over the long weekend comparing the two diffusers.


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## Craigthor (Sep 9, 2007)

If you needed to hold it up in place you could put a rubber O ring or 2 from the hardware store over the tube and slide them down to the plastic cover. 

Craig


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## TLE041 (Jan 16, 2010)

That diffuser must be a new product from ADA. How much did you pay for it?


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## sammyman (Apr 24, 2010)

I picked up that diffuser today from ADA. It was $50 !!! Ouch. Anyway, I am curious to know how this system is working for you or if I should consider using another method?


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## GlassCat594 (Mar 20, 2009)

that diffuser is too nice to hide.


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## Fishly (Jan 8, 2010)

Thank you! :thumbsup: :thumbsup: I've been trying to figure out a way to inject DIY CO2 with an AC for quite a while now.


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## donnoj (Feb 17, 2011)

So, how has this mod worked out?

I have a new Fluval C3 that is similar in design to the AC's and would like to do a similar CO2 mod. 

Would you recommend buying the $50 ADA ball diffuser or sticking with an air-stone or chopsticks?


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## Tamelesstgr (Jan 11, 2008)

What would happen if you just left the end of the tubing open and bubble inside the filter? I have an AC70 I am wanting to try this on.


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## Mxx (Dec 29, 2010)

Tamelesstgr said:


> What would happen if you just left the end of the tubing open and bubble inside the filter? I have an AC70 I am wanting to try this on.


I did this modification, but I didn't have any diffuser to use so I just left the tubing open to bubble inside the filter. Unfortunately the CO2 bubble didn't seem to stay in the filter like that and bubble right back out of the filter through the middle section, so I wasn't seeing much if any difference in my CO2 levels as a result. I suppose they might stay within the filter better if they were much smaller. 

I now have my CO2 off though, as I couldn't get any sort of a consistent bubble rate and one day discovered that my rate of a bubble every few seconds had turned into constant CO2 stream which would have suffocated my fish if I hadn't reacted immediately. So I'm looking for a new needle valve now to add in-line.


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## Mxx (Dec 29, 2010)

I bought an inexpensive ceramic disk nano diffuser, but it looks larger than it did in the photo and still doesn't fit under that plate by the impeller. So I was about to start to modify it by sawing it into sections and then reassembling it, but then I went and rummaged through the kitchen until I found a chopstick. Chopstick piece works fine, but it does make a little almost squeaky noise whenever bubbles come out. 

By the way, how many bubbles per second do you find to be the best in order to achieve 20-30 ppm in an Edge?


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## Kibblemania1414 (Feb 1, 2011)

very nice, i will have to do that with my aquaclear HOB filter. thank you!


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## rj55021 (Apr 4, 2011)

Wow! 

I will definitely try it!

THanks


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## rj55021 (Apr 4, 2011)

Do not using the chopstick piece makes any difference at the end?????


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## jcgd (Feb 18, 2004)

Great mod. I actually did this with my filter a few months ago, but I didn't put a diffuser in at all, just stuck the tubing through the hole. The impeller chops it up and it gets caught in the media. Works like a charm.

I also turn off the filter every day to feed baby brine, and when I power it back up it is still able to prime, even with the hole clogged.


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## FunkyMonk (Feb 24, 2012)

very nice mod here. I like the ada diffusor in the tank! keep up the good work! I have to try this now.


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## beedee (Jul 1, 2010)

i'm going to give this a shot tonight! i'll try the no chopstick method first. (only because i dont have any floating around yet)


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## Gnomecatcher (Sep 8, 2011)

Don't you get a lot of CO2 offgassed as the water flows out the filter? I would imagine that it would be difficult to keep up the amount of CO2 in the water column.


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## AirstoND (Jun 17, 2011)

Gnomecatcher said:


> Don't you get a lot of CO2 offgassed as the water flows out the filter? I would imagine that it would be difficult to keep up the amount of CO2 in the water column.


I also agree with Gnomecatcher on this, unless you have plants in HOB or have a very high outflow rate. 

I am also seeking a method such as a bubble ladder or glass bell to keep CO2 in longer contact with water.


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## Vermino (Jun 14, 2012)

AirstoND said:


> I also agree with Gnomecatcher on this, unless you have plants in HOB or have a very high outflow rate.
> 
> I am also seeking a method such as a bubble ladder or glass bell to keep CO2 in longer contact with water.


https://sites.google.com/site/aquaristikedge/technik/versteckter-co2-topper


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## Cwy0608 (Aug 27, 2013)

anyone checked how efficient the chopstick is?


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## Chrisinator (Jun 5, 2008)

Let us know how you do!


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## MERSF559 (Oct 18, 2013)

possibly show a step by step video on how to do this? im the type of person that wants to make sure im doing it right lol ihave a aqua clear hob filter and this would be a great addition!


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