# CO2 Diffuser Options for Nano Tank



## Hephaestus (Feb 2, 2017)

Hey there.
I am in the process of setting up a new 7.5gal (12"x12"x12" cube) rimless nano tank. I'm going to be using an Eheim 2211 canister for filtration. I am looking for the best option for delivering pressurized CO2 into the tank. I have considered building a DIY Gregg style reactor, but this tank is going to be sitting on my desk so I will have limited space for equipment.

Would an inline reactor be better, or are there any in aquarium options that diffuse well without wasting too much CO2?

I am kind of interested in this option:

https://www.amazon.com/dp/B01GUT0HRA/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=1BP1PPO8F24R7&coliid=IYIJ3Q1XBDDQU&psc=1

Would it be any better than a simple sintered glass disk?

What about the Atomic diffusers from GLA (inline or in tank)?

Aquarium CO2 Diffuser | Atomic - Cal Aqua Labs - Pollen - Nano

For reference, I am going to be planting Staurogyne repens, Lilaeopsis brasiliensis, Alternanthera reineckii "mini", and Rotala wallichii in this tank.

Thanks in advance.


----------



## PlantedRich (Jul 21, 2010)

I like your approach to look for options and not jump at the first offer! 
I am a fan of the Grigg's and find I can adjust the size to fit the need. But I can also see places where they would be really awkward. Having the water come into the top and out the bottom to the tank can lead to problems. 
So options are needed, for sure. I would not want the second options due to the mass of bubbles going pretty much straight up and out of the tank. Like an airstone only finer/smaller bubbles? Not my thing to little to bubbles and it mucks up the glass where they break. 
The first option looks like a pretty good one to me. Canister down under the desk, possibly? That would seem to be a good place to keep the rest of the gear down and out of sight as well. I find dwell time for the CO2 to go into the water is a critical factor. CO2 does move into the water all by itself, given time, so I find the longer I let the two hang together, the fewer bubbles come out in the tank and it stays longer. I've tried the rector before the filter and it did not work as it eventually filled the can with bubbles and the impeller stopped pumping. But on the output side looks ideal for you. 
Worst case might be that it did not totally get the bubbles dissolved but that might not be a real killer, either. Using a really small, low flow Zoomed filter on a twenty long, I got bubbles but when I added enough tubing (14"?) to extend the input to the far end of the tank, the bubbles had time to go away. 
A coil of tubing with broad sweeping curves doesn't slow flow too much. Perhaps, if there was worst case and bubbles, simply adding a coil of tubing under the desk might solve any potential trouble. 
I've wondered if a simple coil of tubing like ten feet long might do the same as a PVC reactor? Not tried it, though. Seems too simple. 
Feel like being the "guinea pig" and letting me know?:laugh2:


----------



## Hephaestus (Feb 2, 2017)

The canister filter will either sit under my desk, or inside a stand for a 10gal that will sit next to the desk. There should only be about a 36-48" run of hose from the filter to the tank. If I put it in the stand, I could have some room for a larger reactor, but my main concern with a larger reactor is how much it may reduce the flow from my 2211. They are pretty low flow to start with, and combining a large reactor and 36" of head height may slow the flow too much.

The first option seems to be very simple and elegant while not impeding flow too much or being very large.

As far as bubble diffusers (like the Atomic in-tank diffusers), I'm not opposed to some bubbles in the tank, as long as most of the CO2 isn't just flowing out the top of the water rather than diffusing into the water column.


----------



## BeastMaster (Dec 17, 2012)

Hi Hephaestus!
I've been using the Atomic/UpAqua inline diffusers on all my set-ups. I hook up my diffusers just after the intakes & set CO2 bubble rates @ less than 1bps. The contact time & agitation produced by the Ehiem canister (2211 & 2213) impellers have worked extremely well over the 3yrs of operation. HC & Monte Carlo continue to grow well in my tanks. Hope this helps.


----------



## Hephaestus (Feb 2, 2017)

BeastMaster said:


> Hi Hephaestus!
> I've been using the Atomic/UpAqua inline diffusers on all my set-ups. I hook up my diffusers just after the intakes & set CO2 bubble rates @ less than 1bps. The contact time & agitation produced by the Ehiem canister (2211 & 2213) impellers have worked extremely well over the 3yrs of operation. HC & Monte Carlo continue to grow well in my tanks. Hope this helps.


So you've got the CO2 injecting prior to the Eheim, so that the impeller will help break up the bubbles? Do you have any issues with CO2 building up inside the canister, or with noise from cavitation?

I'd really like to use a small inline diffuser for space reasons, but I've seen enough bad reviews online to make me hesitate a little. The reason I like the first one linked is that its high quality (either stainless steel or aluminum and acrylic tube). The UpAqua ones seem to have issues with crazing and cracking over time.


----------



## Aqua99 (Jan 6, 2017)

I'm running the option you have in that first link on my little 6gal. The nice thing is that it's so small and easy to conceal. I still get micro-bubbles but not many (sunsun 602). it's essentially a glass type diffuser that you don't have to look at in the tank, with a little better diffusion and tiny bubbles. I have no problem getting my CO2 where it needs to be in that tank.

I have another small diy option I'll be trying out this week as well as a small reactor that works nicely. I'll try to post some pics when I get home.


----------



## Hephaestus (Feb 2, 2017)

Aqua99 said:


> I'm running the option you have in that first link on my little 6gal. The nice thing is that it's so small and easy to conceal. I still get micro-bubbles but not many (sunsun 602). it's essentially a glass type diffuser that you don't have to look at in the tank, with a little better diffusion and tiny bubbles. I have no problem getting my CO2 where it needs to be in that tank.
> 
> I have another small diy option I'll be trying out this week as well as a small reactor that works nicely. I'll try to post some pics when I get home.


Glad to get some first hand experience advice. I'd appreciate any pics you can share! Do you have to do much, if any, fiddling with it once it was set up?

I am leaning towards the first one. It's relatively inexpensive and seems like a pretty simple design.


----------



## Aqua99 (Jan 6, 2017)

My most effective reactor for my 2211 is this awkward looking thing (strange shape and inefficient 90*s to fit where I need it in a small space). The main body is made from 1.25" pvc. I get zero bubbles or even fine mist in the tank. It does kill the flow a little on my 2211 but it works well for the little tank it's used on.










I'm trying this next one out on my little 6gal with my 602b. It's more or less just something stupid I'm messing around with (spare parts lying around and a $12 ss mesh strainer). It's based less on "dwell time" and more about using the 602's flow to beat the bubbles up against the top of the strainer before passing through the mesh (#30 mesh so not much impact on flow). There's a small diffuser inside the CO2 input port to get things off to a better start before hitting the strainer.










The one you were interested in (in that link of yours) works pretty well like I was saying. The build quality seemed good and it reminds me of those bubble counters people build directly onto their regs. The only place where it's going to have any decent force applied is to the hose barb fittings, and that whole portion is sturdy aluminum. Very little to go wrong and a diffuser disk you can cheaply/easily replace if needed. Mine is only about 1' before my output dumps into my tank. It might work even better for you if you mount it low and have a good 3' run before it dumps into your tank to aid in diffusing. The nice part is that it has no negative effects on flow rate. Overall, I'd say I only see about 25% of the bubbles I saw with the standard in-tank glass body diffuser.

Bump: Sorry- my only pics of that one specifically would look horrible and dark behind my tv console! 

There is no adjusting needed besides finding the pressure you want your reg to supply it and tweaking your bubble count. Overall, I'd say it's a nice mix between an in-tank diffuser and a full blown reactor.


----------



## Hephaestus (Feb 2, 2017)

Nice! I think I'm going to go with the first one I linked to. If it doesn't work well, I can always try something else. Maybe a DIY reactor if I can come up with a design small enough to suit me .

Thanks for taking the time to comment and share pictures.


----------



## Aqua99 (Jan 6, 2017)

@;


Hephaestus said:


> Nice! I think I'm going to go with the first one I linked to. If it doesn't work well, I can always try something else. Maybe a DIY reactor if I can come up with a design small enough to suit me .
> 
> Thanks for taking the time to comment and share pictures.


No problem! I think it might work well in your situation. Good thing is it's a minimal investment. Good luck! :smile2:


----------



## BeastMaster (Dec 17, 2012)

Hephaestus said:


> So you've got the CO2 injecting prior to the Eheim, so that the impeller will help break up the bubbles? Do you have any issues with CO2 building up inside the canister, or with noise from cavitation?
> 
> I'd really like to use a small inline diffuser for space reasons, but I've seen enough bad reviews online to make me hesitate a little. The reason I like the first one linked is that its high quality (either stainless steel or aluminum and acrylic tube). The UpAqua ones seem to have issues with crazing and cracking over time.


My bubble rate is low enough (>1bps) that there is no excess to build up in the canister hence, no trapping of CO2 gas or cavitation noise. The impeller agitates the CO2 laden water to promote supersaturation. I know that the set-up works for me cause of the formation of micro bubbles at the surface in the tank & "pearling" from the plants.

I have looked at the UpAqua/Atomic diffusers when I first started planted aquariums & back then the diffusers had a different casing then the 2nd generation ones now available. These 2nd generation casings seem to be the ones that develop the plastic crazing. I have 5 set ups using the 1st generation diffusers and not had any issues over CO2 use.

The metallic diffusers look promising. They were not available when I started pressurized CO2. Wouldn't mind testing one on one of my tanks. Good luck & keep posting your progress.


----------



## kyle3 (May 26, 2005)

Hephaestus said:


> Nice! I think I'm going to go with the first one I linked to. If it doesn't work well, I can always try something else. Maybe a DIY reactor if I can come up with a design small enough to suit me .
> 
> Thanks for taking the time to comment and share pictures.


I would be really interested to hear how you are liking this diffuser?

and if you chose to put it on the intake or outflow side?

thanks!!


----------

