# Best and simplest way to inject CO2?



## greenink

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.






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?


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## George Farmer

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.


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## greenink

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.


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## GHNelson

For Sale on ebay also George.
hoggie


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## foxfish

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...


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## greenink

Really don't find that. Maybe am just lucky but never get any burping, just crystal clear water and lime green drop checkers.


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## Spnl

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


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## pepedopolous

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


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## greenink

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.


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## AverageWhiteBloke

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?


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## GillesF

AverageWhiteBloke said:


> 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?


 
Nope, no effect on bacteria


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## AverageWhiteBloke

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?


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## greenink

Think everyone else can see!


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## AverageWhiteBloke

Hmm strange one!
 
When I right click the image and click view I can so probably a browser setting on my end.


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## weasel

GillesF said:


> Nope, no effect on bacteria


 
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...


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## AverageWhiteBloke

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.


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## weasel

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..


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## greenink

There's a long thread on this somewhere: conclusion was doesn't affect bacteria as O2 and CO2 aren't mutually exclusive.


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## foxfish

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!


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## GillesF

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...


 
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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## weasel

Fully agree foxfish,I think planted tanks get away with it because most of the bacteria is probably heterotrophic in the canister filter even without c02.heterotrophic bacteria are generally considered to be organic sludge degraders. They are mostly from the genera Bacillus and Pseudomonas. Most of these are facultative anaerobes; meaning they can function with or without oxygen. They will do completely different functions depending on the level of dissolved oxygen present.


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## weasel

GillesF said:


> 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


 Thanks i'd like to read this..


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## ian_m

CO2 and oxygen can exist in the water independent of the other. Adding CO2 does not expel oxygen. Fish & bacteria carry on breathing O2, the presence of CO2 (in acceptable amounts) does not affect them .

CO2 is toxic in air eg in a pub cellar as it excludes the oxygen, so you asphyxiate due to lack of oxygen not excess CO2.

Fish suffer with high levels of CO2 in the water, even if the water is saturated with oxygen, due to the CO2 coming out of solution in their gills, thus excluding the oxygen.


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## weasel

ian_m said:


> CO2 and oxygen can exist in the water independent of the other. Adding CO2 does not expel oxygen. Fish & bacteria carry on breathing O2, the presence of CO2 (in acceptable amounts) does not affect them .
> 
> CO2 is toxic in air eg in a pub cellar as it excludes the oxygen, so you asphyxiate due to lack of oxygen not excess CO2.
> 
> Fish suffer with high levels of CO2 in the water, even if the water is saturated with oxygen, due to the CO2 coming out of solution in their gills, thus excluding the oxygen.


yes in acceptable amounts but if your flooding a canister filter with C02 which has already limited oxygen then surely the nitrifying bacteria suffer,even more than the fish.especially the last few hours before the lights come on in the morning...


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## ian_m

weasel said:


> yes in acceptable amounts but if your flooding a canister filter with C02 which has already limited oxygen then surely the nitrifying bacteria suffer,even more than the fish.especially the last few hours before the lights come on in the morning...


The oxygen won't be limited, adding CO2 does not alter the amount of oxygen in the water.

I would be more worried about the CO2 attacking the rubber filter seals. CO2 dissolves in rubber, making it either soft or hard, depending on rubber type. This is why the fire extinguisher uses a Teflon sealing washer and you have to use special CO2 piping.


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## ceg4048

weasel said:


> 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..


This is a gross oversimplification of a complicated physiological process.
Firstly, the assumption that dissolved CO2 in the water column somehow affects the dissolved Oxygen content of the water is inaccurate. Do a search on gas Partial Pressure. The solution of any gas has nothing to do with the availability of any other gas dissolved in the same water.

Secondly, many of the nitrifying bacteria, such as nitrosomonas, are actually chemotrophic autotrophs, which means that they are able to fix Carbon in exactly the same way that plants do by uptaking CO2 and then using the CO2 in a Calvin Cycle procedure which fabricates glucose. Other micro-organisms in the tank and filter are chemotrophic heterotrophs, which means they are unable to fix Carbon from inorganic CO2, so they get their Carbon from organic carbohydrates which are the pollutants in the tank, and which are also produced and exported by the fish and plants. There are a wide variety of germs in the tank water, in the sediment and in the filter. They are not affected by CO2 in the way that fauna are affected. The toxic mechanism of CO2, called hypercapnia, is a function of the way in which higher organisms collects Oxygen, primarily, but not limited to the function of the hemoglobin (or hemocyanin in some inverts). CO2, through it's action of lowering the blood pH, interferes with the process by which these Oxygen carrying proteins bind the Oxygen, and so lowers the Oxygen carrying ability of the blood. Bacteria and archaea do not use this mechanism and are therefore immune to that particular debilitating effect. Check the video links in the thread not enough oxygen... | UK Aquatic Plant Society

Thirdly, CO2 dissolved in the water column and then sucked into the filter is exactly the same as pumping CO2 into the filter. Does anyone imagine that 30ppm dissolved CO2 in the tank water somehow falls to zero when that water enters the filter, and then somehow 30ppm reappears after the water exits the filter? Whatever concentration of any gas in the tank is also in the filter.




foxfish said:


> 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.


What about the Oxygen added to the water column by plants during the photoperiod? Doesn't the gas find it's way into the filter as well as into the sediment? Naturally, at night, when there is no added Oxygen, it would be better to have aeration such as with a sump or with a wet/dry.



foxfish said:


> 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!


And once we understand why it works, what the limitations are, as well as what the benefits are then we can proceed to modify the perspective.

Cheers,


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## weasel

Thanks for the detailed explanation Ceg..
With the C02 reducing the pH of the water doesnt this lower the efficiancy of the bacteria as a pH lower than 6.7 can significantly reduce productivity.I understand optimum is between 7.2 and 8..Is it also true theres many types of bacteria that convert ammonia but only a few that convert nitrites....

Thanks


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## AverageWhiteBloke

> Thirdly, CO2 dissolved in the water column and then sucked into the filter is exactly the same as pumping CO2 into the filter. Does anyone imagine that 30ppm dissolved CO2 in the tank water somehow falls to zero when that water enters the filter, and then somehow 30ppm reappears after the water exits the filter? Whatever concentration of any gas in the tank is also in the filter.


Reading this post with interest but on the above point, I can see how the co2 levels would be the same inside the canister as in the rest of the tank with it being in equilibrium. Would direct exposure to pure co2 in the case of trapped pockets have a negative impact on the bacteria. I guess this would be minimal though considering the small surface area exposed.


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## weasel

I Suppose it depends on how clean the filter...

Ceg ..At the point of entry of the co2 surely must be higher that 30ppm until it equalizes in the tank...so if the co2 is injected into the filter this would be its highest point of C02 saturation..


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## ceg4048

If there are trapped bubbles in the filter then that means the CO2 is not dissolved. In fact that's one of the major  problems of any diffuser. The rate of solubility of the gas into the water is not as fast as the injection rate. That's why the burping of the filter. At the point of entry, if the CO2 concentration is higher, then more CO2 loving bacteria will develop at that location than at other locations in the filter. At lower pH the NH3<->NH4+ equilibrium shifts to the right, so there is lower concentration of toxic NH3. In any case, the plants, if healthy will uptake NH3/NH4+ so it doesn't really matter that some bacteria are less effective at lower pH. If there is a higher Oxygen due to plants as well as higher CO2 and nutrient content then there is also a higher bacterial population. Bacteria need PO4, Potassium and Iron as well, and all these things are supplied in abundance when we dose the water column. Bacteria are not the only denizens of the filter. Archaea are another life form that do probably most of the work in the Carbon Cycle as well as in the Nitrogen cycle.

Cheers,


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## foxfish

All this suggest to me that if you are using a canister filter for the manufactures designed purpose then concentrating high levels of co2 within the vessel is not a good idea!
I find it hard to believe that the changing conditions inside the filter throughout the day & night, the build up of gas & ph swings are the best environment for consistent & healthy bacteria growth.
Like I have already stated ... This might not actually matter that much but is seems to me you are effectively converting a biological power filter into a co2 reactor -  not nurturing  the ideal biological environment?


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## greenink

Perhaps, but it works for me! Thanks for all the thoughtful responses.


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## weasel

Theres certainly alot going on inside the canister filter,which to me seems like the balance could be upset very easily...until i can understand the workings properly i think i will stick to my sump with aggressive aeration and use more co2 after the biological side...
I think someone like Ceg should start a thread called understanding the working of a co2 injected canister filter and what kind of bacteria does what...lol...


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## dw1305

Hi all,


foxfish said:


> I find it hard to believe that the changing conditions inside the filter throughout the day & night, the build up of gas & ph swings are the best environment for consistent & healthy bacteria growth.





ceg4048 said:


> Secondly, many of the nitrifying bacteria, such as nitrosomonas, are actually chemotrophic autotrophs, which means that they are able to fix Carbon in exactly the same way that plants do by uptaking CO2 and then using the CO2 in a Calvin Cycle procedure which fabricates glucose. Other micro-organisms in the tank and filter are chemotrophic heterotrophs, which means they are unable to fix Carbon from inorganic CO2, so they get their Carbon from organic carbohydrates which are the pollutants in the tank, and which are also produced and exported by the fish and plants. There are a wide variety of germs in the tank water, the sediment and the filter.


Like Clive says, it doesn't matter as much as you might imagine. This is really because the micro-organisms that decompose organic products are a complex assemblage of species that have evolved over billions of years.

We used to have one of these in the lab. <Winogradsky column - Wikipedia, the free encyclopedia>.

If a scarce product like fixed nitrogen (NH3, NO2 etc) is available in any environment, organisms will have evolved to exploit it. Low pH, high levels of CO2 and low levels of oxygen are very common in environments where decomposition is occurring, principally because the bacteria are utilising oxygen (O2) and producing CO2.

The difference is in the end product produced (e.g. CO2 if aerobic decomposition of organic matter is occurring or H2S if anaerobic), and in the efficiency of the process. In our terms biological filtration is all about oxygen, as long as we have enough oxygen everything else is much less important.

A lot of the problems people attribute to low pH etc are really to do with low levels of dissolved oxygen (it is the O- in OH- that is the base) leading to a failure in biological filtration.

*Fish bits*
The practical ramifications of this were why I wrote: "*Aeration and dissolved oxygen in the aquarium":* <plecoplanet: Aeration and dissolved oxygen in the aquarium>.

Some might also be interested in this page on fish physiology and the Bohr-Root effect: < Fish Respiration>.

cheers Darrel


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## ghostsword

Why not use a dedicated canister for it? Lot's of cheap filters online, and if the device is just full of balls and mesh, it will get the co2 disolved, right?


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## weasel

dw1305 said:


> Hi all,
> 
> 
> Like Clive says, it doesn't matter as much as you might imagine. This is really because the micro-organisms that decompose organic products are a complex assemblage of species that have evolved over billions of years.
> 
> We used to have one of these in the lab. <Winogradsky column - Wikipedia, the free encyclopedia>.
> 
> If a scarce product like fixed nitrogen (NH3, NO2 etc) is available in any environment, organisms will have evolved to exploit it. Low pH, high levels of CO2 and low levels of oxygen are very common in environments where decomposition is occurring, principally because the bacteria are utilising oxygen (O2) and producing CO2.
> 
> The difference is in the end product produced (e.g. CO2 if aerobic decomposition of organic matter is occurring or H2S if anaerobic), and in the efficiency of the process. In our terms biological filtration is all about oxygen, as long as we have enough oxygen everything else is much less important.
> 
> A lot of the problems people attribute to low pH etc are really to do with low levels of dissolved oxygen (it is the O- in OH- that is the base) leading to a failure in biological filtration.
> 
> *Fish bits*
> The practical ramifications of this were why I wrote: "*Aeration and dissolved oxygen in the aquarium":* <plecoplanet: Aeration and dissolved oxygen in the aquarium>.
> 
> Some might also be interested in this page on fish physiology and the Bohr-Root effect: < Fish Respiration>.
> 
> cheers Darrel


 
Just read your artical Darrel"*Aeration and dissolved oxygen in the aquarium":*,well impressed with the detail you included.
Thanks excellent read.


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## weasel

I still believe the best thing is not to have any build up in your filter,a build up will contain alsorts of nasty bacteria,excellarating any illness your fish have,making a minor problem a major..but obviously a plant only tank makes this irrelavent...


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## dw1305

Hi all,


weasel said:


> Thanks excellent read.


Thanks for reading.


weasel said:


> I still believe the best thing is not to have any build up in your filter,a build up will contain alsorts of nasty bacteria,excellarating any illness your fish have,making a minor problem a major..but obviously a plant only tank makes this irrelavent...


You definitely don't want a build up of CO2 in the filter, but I'm not sure that it will have any major microbiological effects.

The advantage of planted tanks is a lot to do with the net oxygen increase. Adding CO2 is a slightly different issue. I don't use CO2, this is because:

I'm not particularly interested in fast plant growth.
I'm pretty tight with my money.
but principally I don't want to accidentally asphyxiate my fish.
In a tank without any livestock it would be slightly different.

cheers Darrel


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## ceg4048

foxfish said:


> All this suggest to me that if you are using a canister filter for the manufactures designed purpose then concentrating high levels of co2 within the vessel is not a good idea!
> I find it hard to believe that the changing conditions inside the filter throughout the day & night, the build up of gas & ph swings are the best environment for consistent & healthy bacteria growth.
> Like I have already stated ... This might not actually matter that much but is seems to me you are effectively converting a biological power filter into a co2 reactor - not nurturing the ideal biological environment?


The idea of nurturing the ideal biological environment is little bit of tunnel vision and maybe many sump lovers subscribe to this. I think it's better to view the tank as a system upon which the bacterial load is a foundation. The foundation needs to be strong enough to support the rest of the system but it doesn't have to be so strong to the exclusion of all other components. There is a lot of leeway. In a brand new tank the development of the bacterial load is critical to success because the population and diversity is weak. So we do as much as we can to get it strong. Once it's up and running then the bacterial load is versatile and flexible. As Darrel mentions, there are more than one species doing similar jobs so we really don't need to worry too much unless we are adding chemicals that specifically destroy bacteria. CO2 is NOT one of these destructive chemicals.

Also, it's probably another fantasy that manufacturers know any more about microbiology than we do. Filter manufacturers know a lot about building plastic buckets and attaching pumps to those buckets. That's about it. Some manufacturers of aquatic products don't even know the first thing about the science of the product that they build. They are simply businessmen who see and fill a market niche. How long ago was it that DC vendors included instructions to use tank water to fill the DC? A totally inappropriate instruction, rendering an already poor tool even more pathetic. WE are the ones who figured out how to use the DC in a way NOT sanctioned by the manufacturer, and which, it turns out works 100% better than "manufactures designed purpose". These manufacturers are the same bozos who remove the media from the bucket when doing the flow rate tests to artificially enhance their official flow throughput ratings. WE are the ones that had to come up with a better formula for figuring out what filter rating to use to give ourselves a better chance of success in a CO2 injected tank.

So doubling up the use of a canister filter to act as both filter and CO2 diffuser does no harm to the microbes and can yield a much better rate of success than using an in tank diffuser, ESPECIALLY if the tank size is large. I mean, look at this recent example=> Low-light, Hi-tech planted tank | UK Aquatic Plant Society

A 500L tank using the filter as a diffuser. How healthy is that system? Please people, can we get rational about this? How we feel about some process or procedure should be evaluated within the context of facts and data. Feelings do not necessarily equate to reality. Feelings without supportive data is the reason we get into trouble.

Cheers,


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## ghostsword

Can this thread be shared on Facebook? Amazing learning material here..


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## weasel

ceg4048 said:


> Also, it's probably another fantasy that manufactures know any more about microbiology than we do. Filter manufacturers know a lot about building plastic buckets and attaching pumps to those buckets. That's about it. Some manufacturers of aquatic products don't even know the first thing about the science of the product that they build. They are simply businessmen who see and fill a market niche. How long ago was it that DC vendors included instructions to use tank water to fill the DC? A totally inappropriate instruction, rendering an already poor tool even more pathetic. WE are the ones who figured out how to use the DC in a way NOT sanctioned by the manufacturer, and which, it turns out works 100% better than "manufactures designed purpose". These manufacturers are the same bozos who remove the media from the bucket when doing the flow rate tests to artificially enhance their official flow throughput ratings. WE are the ones that had to come up with a better formula for figuring out what filter rating to use to give ourselves a better chance of success in a CO2 injected tank.


Theres only one filter designer I know that will tell the truth about his filtration and then give 100% after service,satisfaction and thats Peter waddington.designer of the ERIC filter,which does exactly as he says with no hidden extras,or add ons..The rest is as you say just a big money earner..
Hard to believe but koi are living perfectly ok,with nitrite readings of 5.0ppm on initial start up of filter,totaly illiminating new pond syndrome..(if there is such a thing)
Im new to this planted tank lark, so i ask these questions in a way to get some serious responses,
You can get some really conflicting answers on forums and i believe i now have found people who know what there taking about,you cant knock the man who seeks the truth..

Thanks from a keen learner..


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## greenink

ghostsword said:


> Can this thread be shared on Facebook? Amazing learning material here..



Agree. Feel like I accidentally convened a meeting of the planted tank Jedi council.


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## ghostsword

I went to check out the filters Eric has.. ERIC Koi Pond Filtration | The ERIC Range of Koi Pond Filters

They look nice, but expensive.. 

I still maintain that if one wants "best and simplest" co2 diffusion then a dedicated filter with just balls will work fine.. 

I am making a small diffuser using the eheim 350's skimmers, inside a black pvc pipe, water and co2 is sucked up through them (from the top) and then pushed out of the bottom, and you can also make a directional nozzle out of plastic.. this will replace the koralias.. it is still under prototype drawings, but as soon as I have a working and tested then I can share more.


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## oldbloke

Dumb question, but how exactly do these CO2 diffusers work?
I assume a pocket of gas builds up in the top of the tube, is this then just absorbed into the water?
And please remember, I am old and simple and need things spelling out......


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## foxfish

I think you mean reactors?
If so, then they work on the principle of keeping the Co2 bubbles in suspension against a flow of water in a confined space 

If you had the space, you could for example, have a 5m high length of 50mm pipe with a co2 bubble rising to the top from the bottom.
The bubble would probably completely dissolve into the water before it reached the top
.
However if we flow some water down the pipe against the rising bubble, then the bubbles assent will be slowed down & the bubble would dissolve way before reaching the top!
So if we design a method of keeping the bubbles in suspension against a flow of water in a smaller space, we have a reactor
.
Unfortunately this is not quite as easy to achieve inside a really small vessel without a certain amount of bubbles escaping or without a large build up of undissolved C02 !!
The most effective method I have every used by far revolves (nice pun) around a vortex design, where the water is sent spinning inside a tube so the bubble has to travel hundreds of times around the tube before it would ever reach the outlet!


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## oldbloke

Thanks Foxfish.
Yes, reactor!
So, the CO2 inlet needs to be not to far down the tube for the bubble to be swept away and not too near the top so it doesn't pop straight to the surface?
If there is a pocket of CO2 at the top, does some of this get dissolved through the surface?

Cheers.


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## foxfish

Yes C02 very often gets accumulated in the top & works against the incoming water, this is not ideal but pretty normal for most DIY reactors.
One of the problems with coloured PVC reactors is that you cant actually see what is happening inside or to what extent the (if any)  build up of gas has developed into.
With a clear vessel not only can you tell when all the accumulated gas is used but you can also adjust the length of the co2 feed line up or down to get the best results.
You can buy Chinese made intank vortex reactors for £20 that work extremely well!


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## oldbloke

Great stuff, thanks for that.


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## MikeJojo

Hi,

My name is Michael and this is my first post here although I read this forum a lot so far. Great place to seek information an advice it is. You guys know a bit about aquatics . 

I wanted to say that aqua medic tee connector is really great idea. Wondered only if I need any hose/tube clamp/clip on co2 end for safety reason or the tubing will stay on even I switch co2 at night? Clamps are kind of obvious thing for me on hose ends. 

Mike


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## greenink

I've found it works brilliantly with no clips of any kind. Have CO2 off at night also. Here's where this set up went from


17 May bookcase tank by mike@ukaps, on Flickr

And to - in matter of days


IMG_2404 by mike@ukaps, on Flickr

(Welcome to the forum - I knew nothing about planted tanks and this forum took me from an underwater submarine to half way competency!)


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## MikeJojo

That is great result!  I'll do clamps anyway. Just can't stand an idea of flood in my room but it's good to know it does well without them. 

Do you have it on intake? 

Mike


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## Spnl

I tried this on my Fluval 406 filter. The fluval hoses were incredibly hard to get over the connectors on the T piece, very tight but still leaked, so unfortunately I had to take it off.
Instead, using the same idea, I put a ceramic diffuser immediately beneath the filter inlet.
This is working well. Downsides are that it has made the filter noisier (it was not silent to begin with), makes a squelching a sound with quite frequent "burps", and there are micro bubbles in the water. I wonder if this is due to relatively poor flow in the Fluval? I do have floss in there so will take that out and see if it helps.
But it has given me the best CO2 dissolution and distribution I have had, although still not perfect. Tank is 350l. Do other people struggle with CO2 in larger tanks (it seems a lot of the planted tanks are smaller than this, but I know others mange much bigger tanks)?


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## greenink

Never had problems. Totally silent (in Eheim). Odd burp every now and then. Yes, on intake. Never clogs, never slows down. Perfect!


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## MikeJojo

Thanks. I'll give it a go. 


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## MikeJojo

Little update. I've done it and works really well. I get burb now and then but that's fine as long as there is no mist in my tank. One more benefit - no more soaking any diffusers or atomizers in bleach over night. Thank you mikeappleby for an idea. 


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## MikeJojo

Hi there. Initially I installed tee connector on intake near the filter and everything was fine till I decided to move it up near intake pipe. Now until co2 is off flow is ok as but when co2 is on I notice drop in flow. FYI I moved tee connector next to aquarium intake pipe due to the fact that when I it was right before filter intake water used to get into co2 tubing and even through up aqua double check valve. 

Where have you guys installed tee connector? Near intake pipe or just before filter intake? Have you encountered such a problems on both occasions as I did?

Mike 


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## greenink

Half way, no problems.


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## MikeJojo

All solved. The same time I moved tee connector I switched from sponge as an intake pipe guard to nylon stocking. That caused too much sucking pressure at intake cuts, two neon tetra got stuck at it :-/ Now less two fish but happy with system again 


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## greenink

Have done a bit of an experiment on this method using a PH pen to check how it works over time. To avoid cross posting results are here:

259L bookcase - rebirth day 19

Upshot is it works fine for smaller tanks, but not for bigger ones. Plus some other stuff.


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