In-line vs. in-tank CO2 diffusers

[WisChris]

I've finally accepted that I need CO2 to pull off what I have in mind for my tank. So here goes, taking the CO2 plunge

About to pull the trigger on the Atomic Paintball CO2 Regulator V2 from Greenleaf Aquariums.

I need to choose in-line diffusion (canister output) vs. in-tank diffuser?

What are the pros & cons of these two different approaches

 

[jbtravis91]

Hey there! I just recently made the same jump that you're about to make.

In-Tank Diffusers:
Pros: I think the only pros of in-tank diffusers are that they don't require a canister filter and they're usually cheaper than in-line diffusers.

Cons: Not as efficient - you're likely to use more CO2 as some will escape through the surface before it gets the chance to react with the surrounding water. In addition, the diffuser will be noticeable in your tank, so if you're going for an ultra-minimalist look, this might not be your cup of tea.

In-Line Diffusers:
Pros: More efficient than in-tank diffusers - by the time the CO2 makes it through the output hose and into my tank, all the bubbles have diffused into the water from the filter. The diffuser is not noticeable at all as it can be tucked below your stand with the output from your canister filter.

Cons: Can be more expensive. Might be a little more of a hassle to set up (CO2 tubing isn't fun anywhere though). Seems to require a canister filter.

Personally, I bought an UP in-line diffuser for ~$30. The quality seems to be decent, and it's been working fine for the last month that I've had it. It was pretty easy to set up too - it's attached to the output of my Eheim 2217 filter.

FYI, I'm running this with a 5lb CO2 canister that I bought from a local home brewery store, a Milwaukee regulator, and a Milwaukee pH controller.

Good luck with your purchases!

 

[ScotJudd]

Hi there. I had to make the same choice and opted for a third choice. I have a tank defuser situated at the bottom of the tank about 6" under the canister inlet. Some of the co2 reaches the surface whilst most is sucked into the filter. My co2 is very stable and my tank water tests remained spot on. Worked for me!

 

[Brian_Nano12g]

I've finally accepted that I need CO2 to pull off what I have in mind for my tank. So here goes, taking the CO2 plunge

About to pull the trigger on the Atomic Paintball CO2 Regulator V2 from Greenleaf Aquariums.

I need to choose in-line diffusion (canister output) vs. in-tank diffuser?

What are the pros & cons of these two different approaches

What size tank do you have? In-line is usually more efficient for larger tanks. It's also feasible in all tank sizes when you don't want more equipment in the tank detracting from the minimalism you'd find in a rimless scape for example (which usually has no background and no tops where mostly everything goes unnoticed). But if the tank is small to medium sized, an in-tank would be fine -- especially if you have good circulation in the tank.

On a side note, I almost purchased that GLA (intense) Atomic Regulator V2 myself. I thought about it and if I were to do get one, I'd actually get the Atomic CO2 Regulator V3 along with a CGA 320 Adapter. That way, I can use it for paintball now, but if I ever wanted to get a larger co2 tank (i.e. 5#, 10#, etc.), I'd be able to use the same regulator for it.

 

[Old Scales]

I did what Scott did also. I have a UV set up on the outflow of the can so adding in line diffusion would have been a mess. The GLA 55mm ceramic diffusor is below the intakes of my Fluval can and my AC50 HOB. None of the CO2 bubbles get to the surface.. OS.

 

[Hawkins409]

I use the UP inline diffuser. Awesome for all of the reasons mentioned. There's a negative, but it can be dealt with. Over time it will slowly clog up and you can't take it apart. I take it out and soak the whole thing in Hydrogen Peroxide. After a few hours, I put it back in and it works great. But meanwhile, my tank hasn't been running, and I think if I had more time I would soak it 12 hours.

Someone suggested to me that I should buy a spare UP inline diffuser so that I always have a clean one on hand. Good idea, but haven't got around to ordering a spare one.

 

[Hawkins409]

So... Order three of them. Two for you and a spare for me. Haha.

 

[WisChris]

What size tank do you have? In-line is usually more efficient for larger tanks. It's also feasible in all tank sizes when you don't want more equipment in the tank detracting from the minimalism you'd find in a rimless scape for example (which usually has no background and no tops where mostly everything goes unnoticed). But if the tank is small to medium sized, an in-tank would be fine -- especially if you have good circulation in the tank.

On a side note, I almost purchased that GLA (intense) Atomic Regulator V2 myself. I thought about it and if I were to do get one, I'd actually get the Atomic CO2 Regulator V3 along with a CGA 320 Adapter. That way, I can use it for paintball now, but if I ever wanted to get a larger co2 tank (i.e. 5#, 10#, etc.), I'd be able to use the same regulator for it.

Hi Brian,
I've got a 26 bow. I'd like to keep the hardware as invisible as possible…The in-tank diffusers look pretty inconspicuous, but that stiff CO2 tubing looks like a pain to shape & install. The in-line sounds a bit complicated to clean, though? My C-220 will move the water pretty good, so I bet I'd be able to suck up and circulate the CO2 pretty well. Decisions, decisions

 

[Brian_Nano12g]

I have a 26g bow at my parents' house. I use an Aquatek paintball CO2 regulator and a basic fluval ceramic diffuser. My canister is a fluval 306. Anyways, I'm getting good co2 dissolution with my setup... my drop checker is always a happy green by the time the lights come on. You'd be fine to go either way. The in tank diffuser works great for me and it's not even atomic.

 

[WisChris]

Thank you OS, Brian, jbtravis, scottjudd & hawkins.

I am being so indecisive, I hate that:?
I really like the concept & clean look of the inline diffusers. But that set-up seems more difficult to tear down and clean. I'm having nightmares about leaks & spills. Maybe I am over thinking this
Hoping I can come to a conclusion & get one ordered thru GLA today.
Thanks again

 

[aqua_chem]

I don't know that there is an efficiency advantage to inline diffusers, being as the bubbles are only in the plumbing for a matter of seconds before being shot into the tank, often near the surface where they can quickly escape. To me, the argument of inline vs in-tank diffusers comes down to the aesthetics of minimal tank clutter vs ease of maintenance, as inlines aren't easily removed and serviced without taking your plumbing apart.

 

[WisChris]

I have a 26g bow at my parents' house. I use an Aquatek paintball CO2 regulator and a basic fluval ceramic diffuser. My canister is a fluval 306. Anyways, I'm getting good co2 dissolution with my setup... my drop checker is always a happy green by the time the lights come on. You'd be fine to go either way. The in tank diffuser works great for me and it's not even atomic.

Thanks Brian, I'm going to take your advice and go for the Atomic CO2 Regulator V3 and run it off a 2.5 lb tank with CGA 320 connection.

Think I'm gonna stick to in-tank diffusion. Think I'll start a new thread as now I'm wondering about how to best manage a 20-30 ppm level. Seems like many folks don't use a drop checker, but I don't wanna stress my fish & become an algae farmer

 

[WisChris]

I did what Scott did also. I have a UV set up on the outflow of the can so adding in line diffusion would have been a mess. The GLA 55mm ceramic diffusor is below the intakes of my Fluval can and my AC50 HOB. None of the CO2 bubbles get to the surface.. OS.

Thanks OS…BTW your new 'scape is beautiful and your journal thread is full of knowledge and very entertaining as well!

Been e-mailing Orlando at GLA, he's been real helpful. Trouble is, for every question he answers, I seem to come up with 2 more

Think I'm gonna stick with an in-tank diffuser and run an Atomic V3 off a 2.5 lb cylinder.

Think I'll start a new thread as I'm struggling with how to keep the flora & fauna happy and keep this thing between 20 & 30 ppm CO2.

 

[Old Scales]

I'll be glad to help anyway I can as I'm sure many others will. For me a drop checker keeps the "unknown" away. I hate unknowns. Yeah, some say they're not completely accurate, but it's more accurate than nothing. LOL. OS.

 

[WisChris]

I'll be glad to help anyway I can as I'm sure many others will. For me a drop checker keeps the "unknown" away. I hate unknowns. Yeah, some say they're not completely accurate, but it's more accurate than nothing. LOL. OS.

Thanks OS, I need all of the help I can get

Think I'm gonna stick to 20 oz paintable cylinders as I can fill them locally at Dick's Sporting Goods. The 2.5 & 5 lb tanks , although longer-lasting, will be a hassle for me to fill.

I want to go conservative and shoot for 15-20 ppm. I have a pretty hectic life & don't want to gas my fish. I'm not sure if a drop checker will allow me to dial in on that CO2 level (yellow-green)?

Still debating in-line vs. in-tank, as well...

 

[Richardwm]

I also debated this for a while then I stumbled upon co2 reactor. Close too 100% diffusion less waste and the tank last longer also tons of cheap easy DIY projects for it here is mine made from a house hold water filter housing modified to accept co2 hose in the bottom.