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Best and simplest way to inject CO2?

greenink

greenink

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Joined
2 May 2011
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Location
London
I've tried lots of in-line approaches...

AM1000 reactor: good diffusion, crystal clear water, too noisy, gets dirty and blocks flow
UP diffuser: bubbles too annoying if post-filter; crystal clear if pre-filter; but slowly gets blocked with limescale and needs cleaning, so needs constant slow adjustment of injection rate

...and have come to the view that the simplest and best way is one of these T-pieces in-line before the filter, injecting CO2 straight into the flow, with a non-return valve immediately next to it preventing any back-flow.

tpiece.tiff

CO2 on a few hours before lights and you get reliable lime green drop checker every time. Can't understand why this isn't the totally standard way of doing it. Crystal clear water, never gets blocked even slightly, cheap as chips, no reduction in flow.

Am I missing something?
 
Some have issues with gas build-up and cavitation (burping) in the filter, especially with higher injection rates. Some have experienced unstable CO2 levels due to this. The jury is out on potential long-term damage to the filter impeller with the constant smashing of bubbles too.

But generally speaking, yes, great idea and well worth trying out. I made a DIY version years ago and it worked a treat. I'm currently using an UP Aqua on the outlet but may well try one of these out for the next scape.

Do you have a link for a retailer?

Thanks for sharing. 🙂
 
Haven't experienced any of those! Goes into Eheim pro 3s in my tanks (of various sizes). Will take potenntially having to replace a filter impeller every few years as a risk I think!

Didn't want to include a retailer link as not sure about sponsors.

Easy to find by googling. Is called 'aqua medic reducing t-piece' and comes in all standard hose widths.
 
If you use a clear canister you would be able to see the limitations! Fine for relatively small amounts of gas but the inevitable build up will happen with increased bubble rate.
The flow inside the filter is very diffused, the gas bubbles inside the filter become trapped in the media & rely of the passing water flow to dissolve them but because of the dissolved flow the bubbles build up & join together causing a build up of pressure that forces its way up & out in the form of much larger bubbles than were introduced.
Like I say good for the smaller tank, take a look at the vid in my link on high flow reactors, I experimented with lots of different internal layouts & found that only the empty chamber avoided a build up of gas.
However you know what they say... if it works for you...
 
I am just in the process of changing from DIY to pressurised co2, so this is really interesting.
Like you I really don't like to see bubbles everywhere.
Given what the others have said above, what sort of bubble rate have you been injecting without any problems?

Also, how do you think this would work if it is inserted immediately after the intake pipe. Just thinking about limiting number of connections outside the tank to reduce risk of leaks. The bubbles would then have to be driven down the inlet pipe. Do you think it would work?

Cheers
 
I really want this to be true but using an UP on the intake, my filter burps all the time (well, not all the time but daily especially by the evening!).

I'm thinking of going back to putting the UP on the outlet and I'll just have to get used to the bubbles...

Still, at a couple of quid for the T-piece it could be worth a try...

Cheers,

P
 
Really high bubble rate: too high to count with a fluval counter and enough to keep 280l tank stable with 3000l/h rated Eheim flow and quite a bit of surface movement...

Filters have those round ceramic balls in every layer, some purigen and the thick sponge - no fine filter floss at all at the moment.

There's no way it will leak - aqua medic stuff is top notch and mainly used for marine setups where failures are even (!) more expensive.

I'm planning on using the same idea to auto-dose EI macros, micros and DIY easycarbo/excel (ie gluteraldehyde mix) direct into water column, though this time post-filter

Seems like I'm just lucky maybe.
 
Is it just me that can't see the image? On another level does large amounts of co2 inside the canister have a negative effect on the bacteria at all?
 
That's good to know, messing with co2 has to be the biggest pain. If the filter burbs now and again it's no big deal I guess as long as it doesn't airlock the filter. What about the image?
 
Hmm strange one!
YZft0wO.png
When I right click the image and click view I can so probably a browser setting on my end.
 
GillesF said:
Nope, no effect on bacteria 🙂
Click to expand...

I disagree, it must have an effect on the bacteria,bacteria in the filter is aerobic,meaning it relies on oxygen to survive,so the bacteria must be reduced if carbon dioxide is pumped into the filter stealing oxygen...
 
My understanding was Co2 and o2 wasn't an either or situation. So lots of both can exist in harmony. Whether high concentrations of Co2 can kill bacteria in the same way as the fish I don't know but plenty of o2 would still be present.
 
C02 will kill anything that needs oxygen to survive....It would probably be the same as if your filter was to starting to track, as it starts to clog if it doesnt get cleaned regular.reducing the flow of oxygen to the nitrosonomas and nitrobacter..your biological filter need 4.3mg of oxygen to convert 1mg of toxic ammonia into nitrate..
 
O2 is definitely the limiting factor inside a canister filter & I simple dont believe the whole canister concept to be very biologically efficient full stop.
However in the high tech planted tank we dont really really to heavily on biological filtration inside the filter due to the biological activity within the main tank & the large water changes.
You dont ofter see folk complain about fish deaths due to poor biological filtration in a planted tank!
From my perspective it just seems like a bad practice to pump C02 into your biological filter but .... it does seem to work for a lot of people!
 
weasel said:
I disagree, it must have an effect on the bacteria,bacteria in the filter is aerobic,meaning it relies on oxygen to survive,so the bacteria must be reduced if carbon dioxide is pumped into the filter stealing oxygen...
Click to expand...

I think it was Clive who explained why it wouldn't affect bacteria in the filter. I'll ask him if he still has the link to that topic.

Cheers
Gilles
 
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