# Using CO2 Efficiently



## jaypeecee (25 Dec 2018)

Hi Folks,

I would like to improve the efficiency of my CO2 usage. I have two related areas of concern:

1  Solubility of CO2 into the tank water

I use an internal ceramic atomizer (Bazooka) that produces a very fine mist of CO2 but, despite this, the microbubbles don't completely dissolve. I use a circulation pump which does an excellent job of moving water around the tank.

2 Loss of CO2 at the water surface

As a consequence of item 1 above, a good many CO2 microbubbles find their way to the water surface at which point they burst. The circulation pump and external filter flow outlet cause only gentle surface agitation - just enough to allow some CO2/O2 exchange.

I have avoided inline CO2 diffusers as I have read of too many horror stories of these malfunctioning thus causing major leaks and flooding. I am also unsure if they do a better job of diffusing CO2 into the water as dwell time is very brief unless the reactor type is used.

Any suggestions?

JPC


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## tiger15 (25 Dec 2018)

CO2 mist is not all that bad as Barr has demonstrated that plants can uptake mist falling on the leaves more efficiently than dissolved carbonic acid.  All Amano set ups use CO2 misting. 

As for CO2 gas bubbles bursting on the surface, it's a loss of no return in open top set up.  But in covered top set ups, I am in the opinion that some lost CO2 is recovered, but I have no data to prove it.  

https://www.ukaps.org/forum/threads/tank-cover-good-or-bad-for-co2.56065/

I agree with you that any in line reactor is vulnerable to leak and for that concern, I don't use it.  If a leak is developed in the plumbing and you don't catch it early, even a slow leak can drain the tank.  I use Tunze reactor, which employs an in-tank power head to drive the reaction, and without external plumbing, there is no opportunity to leak.


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## oscarlloydjohn (25 Dec 2018)

As @tiger15 said, there is some benefit to having CO2 mist coming into contact with leaves. This video might be helpful: 

You could also look into building your own Cerges or Griggs reactor. The qanvee inline diffusers also look pretty sturdy.


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## GHNelson (25 Dec 2018)

Hi
You could add floating plants for more Co2 retention!
hoggie


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## Edvet (26 Dec 2018)

A reactor will be very efficient in dissolving CO2, the more CO2 you use the larger reactor will make it easier. You can DIY a reactor to suit your demands. When i was using CO2 in my 400m gallon I made one about 125 cm long. Member Zeus here made a double setup.


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## TBRO (26 Dec 2018)

+1 on the reactor. Seems to be the only way to get a decent pH drop in my tank without literally pouring in CO2 with the valve open! 

I think a few of Amano’s big tanks must use some kind of in line solution, maybe between the sump and tank? 


Sent from my iPhone using Tapatalk


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## AverageWhiteBloke (26 Dec 2018)

I combine using a bazooka which is the finest mist I've experienced using all the various atomisers on offer and keeping all the equipment in one corner in so far as the intake, lily pipe outlet and bazooka. I have them set up with the bazooka under the intake so it can grab some of this mist and pull it down into the canister to dissolve further and any that manages to get past the intake hits the flow of the out flow and gets pushed round the tank. I guess it's a little bit more effective than say having the bazooka on the opposite side of the tank to the outlet like you see in most setups.

Dissolving co2 is a very wasteful process at the best of times. The vast majority of it just leaves the tank without doing much. Co2 gas just doesn't like living in warm water. It doesn't even want to live in a freezing cold drink for very long. Just wants to enter the atmosphere and play with all the other gases.


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## Oldguy (26 Dec 2018)

jaypeecee said:


> inline CO2 diffusers


I have two inline diffusers, but both are in the tank, with power heads pushing tank water through them. One exhausts through a spray bar, the other through a fish tailed pipe. I too have read about leaking external diffusers hence some rearranged plumbing to get to present set up. I use cover glasses to reduce condensation. Don't know if they enhance CO2 retention. Fish stock appear healthy & active.


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## tiger15 (26 Dec 2018)

I use Tunze reactor, very well made German product. It runs on internal power head and generates about 80/20 dissolved and misty CO2.  I guess you can increase dissolved by extending the pipe, but I rather have 80/20 split, and have a glass top to recover some escaped CO2.  My planted tank is in my living room, and I have zero tolerance of leak.  My filters are multiple HOBs, and I don’t even trust running external canister filters, which IMO is a dangerous equipment that can drain a tank overnight.   Even my CO2 hose check valve is placed inside the tank. By eliminating external plumbing, I eliminate all opportunities to leak.


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## Zeus. (26 Dec 2018)

To make the most of  CO2 injection, the best thing I read is 'you need to use it as CO2 is free' only then will you use it to its full potential


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## jaypeecee (27 Dec 2018)

oscarlloydjohn said:


> As @tiger15 said, there is some benefit to having CO2 mist coming into contact with leaves. This video might be helpful:
> 
> You could also look into building your own Cerges or Griggs reactor. The qanvee inline diffusers also look pretty sturdy.




Hi Oscar,

Thanks for your reply.

The video is very good indeed. I'll check out the Cerges and Griggs reactors.

JPC



hogan53 said:


> Hi
> You could add floating plants for more Co2 retention!
> hoggie



Hi hoggie,

Thanks for your reply.

Your suggestion of adding floating plants is a good one. Never thought of that!

JPC



Edvet said:


> A reactor will be very efficient in dissolving CO2, the more CO2 you use the larger reactor will make it easier. You can DIY a reactor to suit your demands. When i was using CO2 in my 400m gallon I made one about 125 cm long. Member Zeus here made a double setup.



Hi Edvet,

Thanks for your reply.

Using a reactor presents a problem for my setup. The cupboard in my aquarium cabinet is already stuffed with gear so I could only accommodate the smallest of reactors.

JPC



TBRO said:


> +1 on the reactor. Seems to be the only way to get a decent pH drop in my tank without literally pouring in CO2 with the valve open!
> 
> I think a few of Amano’s big tanks must use some kind of in line solution, maybe between the sump and tank?
> 
> ...



Hi TBRO,

Thanks for your reply.

Out of interest, what pH drop do you aim for? I've read elsewhere on UKAPS that people aim for a drop of 1pH but, at some KH values, that would result in a CO2 concentration well in excess of 30ppm.

JPC



AverageWhiteBloke said:


> I combine using a bazooka which is the finest mist I've experienced using all the various atomisers on offer and keeping all the equipment in one corner in so far as the intake, lily pipe outlet and bazooka. I have them set up with the bazooka under the intake so it can grab some of this mist and pull it down into the canister to dissolve further and any that manages to get past the intake hits the flow of the out flow and gets pushed round the tank. I guess it's a little bit more effective than say having the bazooka on the opposite side of the tank to the outlet like you see in most setups.
> 
> Dissolving co2 is a very wasteful process at the best of times. The vast majority of it just leaves the tank without doing much. Co2 gas just doesn't like living in warm water. It doesn't even want to live in a freezing cold drink for very long. Just wants to enter the atmosphere and play with all the other gases.



Hi AWB,

Thanks for your reply.

Glad to meet another Bazooka user! I have been a bit hesitant about locating the Bazooka near the filter intake. I thought the CO2 could get partially trapped in the external canister causing it to 'cough and splutter'. Love your analogy about CO2 entering the atmosphere and playing with all the other gases!

JPC



Oldguy said:


> I have two inline diffusers, but both are in the tank, with power heads pushing tank water through them. One exhausts through a spray bar, the other through a fish tailed pipe. I too have read about leaking external diffusers hence some rearranged plumbing to get to present set up. I use cover glasses to reduce condensation. Don't know if they enhance CO2 retention. Fish stock appear healthy & active.



Hi Oldguy,

Thanks for your reply.

I also have cover glasses but they have cutouts at the two rear corners. I think it's unlikely that any CO2 is retained.

JPC



tiger15 said:


> I use Tunze reactor, very well made German product. It runs on internal power head and generates about 80/20 dissolved and misty CO2.  I guess you can increase dissolved by extending the pipe, but I rather have 80/20 split, and have a glass top to recover some escaped CO2.  My planted tank is in my living room, and I have zero tolerance of leak.  My filters are multiple HOBs, and I don’t even trust running external canister filters, which IMO is a dangerous equipment that can drain a tank overnight.   Even my CO2 hose check valve is placed inside the tank. By eliminating external plumbing, I eliminate all opportunities to leak.
> 
> View attachment 120244



Hi tiger15,

Thanks for your reply.

The Tunze reactor does look interesting. I will check it out. Although I use an external canister filter, I have set up a low voltage water level sensor that switches off the filter if a leak occurs in the filter pipework or the tank itself. I also have a water leak alarm in close proximity to the filter itself. So, keeping my fingers crossed.

JPC



Zeus. said:


> To make the most of  CO2 injection, the best thing I read is 'you need to use it as CO2 is free' only then will you use it to its full potential



Hi Zeus,

Thanks for your reply.

Where can I find your reference to 'you need to use it as CO2 is free'?

JPC


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## Zeus. (27 Dec 2018)

jaypeecee said:


> Out of interest, what pH drop do you aim for? I've read elsewhere on UKAPS that people aim for a drop of 1pH but, at some KH values, that would result in a CO2 concentration well in excess of 30ppm.



a drop of 1.0pH is what is generally advised. My pH drop is well over 1.0pH and my DC is light yellow which can be risky with some livestock. Good surface agitation does seem to help with the higher pH drops for the livestock, but the plants do benefit from higher [CO2]'s . its down to the user plus you do need to try and get the correct pH when the tank has fully degased to know you have acutally got a one unit drop as some tanks take longer than overnight to degas, plus not all pH testing methods are accurate, DC is the best method to see what the approximate pH/[CO2] is IMO/IME 



jaypeecee said:


> Where can I find your reference to 'you need to use it as CO2 is free'?



pH is IMO/IME  

No idea m8  where it was  it was one of the many many posts I read when I started.


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## jaypeecee (27 Dec 2018)

Thanks, Zeus. I'll find the post. Perhaps the livestock can tolerate the higher CO2 levels provided that the O2 level is also high (around 8ppm)?


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## tiger15 (27 Dec 2018)

jaypeecee said:


> Hi tiger15,
> 
> Thanks for your reply.
> 
> ...


Interesting, you’re the only one I know of that install leak protector for your canister set up.  Avoiding in line reactor is a smart move, specially unproven DIY design.    It reduces risk but not a full proof though.  What if water siphons back from the tank to the leak point after the shut down.  Also, alarm works only if you’re home and can hear it.  I don’t want to scare you but the only leak proof is to avoid any external plumbing in the first place.


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## Zeus. (27 Dec 2018)

some of my fish are gasping at the surface at the end of the pH drop but they soon settle down after 15mins and they have been in the tank over a year


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## AverageWhiteBloke (27 Dec 2018)

jaypeecee said:


> Glad to meet another Bazooka user! I have been a bit hesitant about locating the Bazooka near the filter intake. I thought the CO2 could get partially trapped in the external canister causing it to 'cough and splutter'.



I find with the Bazooka the mist is that fine by the time it gets down into the canister travelling through the pipe work its nigh on non existent. Not all of the bubbles get in there either. I don't have issues with it collecting or the filter burping although I have heard some people have, not sure which atomiser they were using and the bubble could have been bigger. 

It depends on how you feel about equipment in the tank. A lot of the reactor type devices like the Sera and similar can be placed inside of the tank on the glass negating the risk of flooding. Some of the newer inline ones seem to be built with metal hose connections so should be safer although I have no experience with these...yet.


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## jaypeecee (27 Dec 2018)

tiger15 said:


> Interesting, you’re the only one I know of that install leak protector for your canister set up.  Avoiding in line reactor is a smart move, specially unproven DIY design.    It reduces risk but not a full proof though.  What if water siphons back from the tank to the leak point after the shut down.  Also, alarm works only if you’re home and can hear it.  I don’t want to scare you but the only leak proof is to avoid any external plumbing in the first place.



Hi tiger15,

Your point about back-siphoning is one that I need a bit longer to think about. Perhaps a non-return valve would be the answer but that would need to be in the tank just in case it leaked! You're partly right about the alarm but some can be WiFi connected, which should enable alerts to be sent to a mobile phone, for example. At the end of the day, nothing is 100% safe. After all, a leak can develop in the tank itself. As with all things in life, it's a question of striking a balance.

JPC


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## tiger15 (28 Dec 2018)

There is an anti siphon hole you can drill into the intake pipe, so if there is a leak, the canister can only lower the water level to certain limit before pumping dry.  

Yes, even with all precautions, the tank seam can leak, and it does happen.  So don’t keep any tanks or place them in the garage or basement where flooding doesn’t matter.  This is equivalent to saying don’t drive because there is no accident proof driving.   But a show tank is a living art, a piece of furniture to show off, so why hide it in the basement no one can appreciate.  So it’s my calculated risk to place my show tanks in the living room but I take maximum precautions to minmize flooding accident.


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## AverageWhiteBloke (28 Dec 2018)

Or, just use an internal filter, then you only have the tank itself to worry about. 

Sent from my STH100-2 using Tapatalk


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## Hades (28 Dec 2018)

tiger15 said:


> My planted tank is in my living room, and I have zero tolerance of leak. My filters are multiple HOBs, and I don’t even trust running external canister filters, which IMO is a dangerous equipment that can drain a tank overnight. Even my CO2 hose check valve is placed inside the tank. By eliminating external plumbing, I eliminate all opportunities to leak.



It's a bit strange to me to stress that much about a possible leak to that extent that you avoid any inline equipment..?
Especially because you say it yourself:



tiger15 said:


> But a show tank is a living art, a piece of furniture to show off, so why hide it in the basement no one can appreciate.



If you want to show off the tank you don't put it in the basement, i agree, but for me the same logic applies for all in tank equipment.
After all the equipment is not what you want to show off, is it? 
It doesn't do the "living art"-part any justice if you have internal filters or HOB (which can also leak by the way...  ), internal reactors or any internal plumbing imo.
Clearly visible equipment doesn't really enhance the look of any tank for me.
I can't really enjoy a tank riddled with in tank equipment so it's not even an option for me, ever...
I have canister filters (5 atm) with inline equipment in my living room for years and never had any leaks. 
For me canister filters and such hold the same risk as a possible leak in the tank itself. (Or a HOB cracking and leaking...) It's part of the game...
And let's be serious: it happens rather rarely provided the proper material, good care and caution so why compromise?

If you don't want anything leaking and you stress about it that hard that you desperately want to eliminate all the opputunities to leak... then you are not there yet i guess, the possibility is still there.
So, it might be better (or even needed) to put some flowers or some plants in your living room instead of a tank filled with water (wanting to get out)... 
But beware: don't over-water those plants though cause the pots might leak a bit...


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## tiger15 (28 Dec 2018)

AverageWhiteBloke said:


> Or, just use an internal filter, then you only have the tank itself to worry about.


True, you can eliminate all opportunities of leak except the tank seam by employing internal filters.  But most internal filters are ugly, and sponge filters are the worse.   There is, however, a poret foam design that I like marketed by this company:

http://www.swisstropicals.com/library/cornerfilter/



Hades said:


> It doesn't do the "living art"-part any justice if you have internal filters or HOB (which can also leak by the way...  ), internal reactors or any internal plumbing imo.
> Clearly visible equipment doesn't really enhance the look of any tank for me.
> I can't really enjoy a tank riddled with in tank equipment so it's not even an option for me, ever...
> I have canister filters (5 atm) with inline equipment in my living room for years and never had any leaks.
> ...


I fully understand why majority of the plant folks prefer canister because of aesthetic, and silence.  No other filters can even come close to competing with canister in those aspects.  I use HOBs as a compromise with safety concern first.  I tried to hide the intake pipes with plants but it's no perfect solution.  HOBs can still leak or overflow, but with no external plumbing (only external box), the opportunities to leak is far far less than canister that has O-rings, clamps and external hoses.  Adding an in line reactor, particularly DIY type, is more opportunities to leak.  I have read enough leak and flood accidents of canister that scare me from using it in my living room.


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## Costa (28 Dec 2018)

Do you know of any reseller of the Gigg's reactor in Europe? I found nilocg in the US but nothing in Europe


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## ian_m (28 Dec 2018)

If wasting worries about flooding due to external equipment look at some of the Aquanano range of tanks. All the pumps and filtration is in a section in rear of the tank. Have decent filtration rate as well, suitable for high tech CO2 tanks.


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## AverageWhiteBloke (28 Dec 2018)

I try whenever I can to keep equipment out of the tank purely for aesthetics. Sometimes people need the function though. A lot of people photo their tanks with equipment removed then put it back in to function. For instance the Twinstar things, eheim surface skimmers and koralia pumps etc. 

Seems anything that's handy is just down right ugly. Best solution is getting an over the top flow rate filter but some people can't afford them.

I think Juwel had the solution which is effectively a Matten filter and enclosed heater inside the tank in a compartment but people didn't want to lose the real estate in the tank. An old Aqua one I had was also a good idea where it had a trickle filter in the lid but it was no good for keeping gas.

In all the years I've been keeping tanks I've never had a canister leak on me. The closest I ever came was using a sera reactor installed out side the tank which relied on the pressure of the tubing on it to make a seal. After a while they mould to shape and lose their seal. Canisters are different though as they generally have a system for tightening up the pipe again. 

Sent from my STH100-2 using Tapatalk


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## Edvet (28 Dec 2018)

AverageWhiteBloke said:


> I've never had a canister leak on me


Neither have i in 25 years, now sumps is something else..............luckily i have tiles.


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## Hades (29 Dec 2018)

AverageWhiteBloke said:


> I try whenever I can to keep equipment out of the tank purely for aesthetics. Sometimes people need the function though. A lot of people photo their tanks with equipment removed then put it back in to function. For instance the Twinstar things, eheim surface skimmers and koralia pumps etc.
> 
> Seems anything that's handy is just down right ugly. Best solution is getting an over the top flow rate filter but some people can't afford them.
> 
> ...



I have two basic, classic eheim canisters on my "high tech" tank to get an over the top flow rate (together rated at 2.000l/h on net 140l of water). 
Inside my tank i only have two sets of lilypipes, a heater and a dropchecker. All placed against the same side panel so not really disturbing (provided they are kept clean).
Two inline diffuser (in front of the canisters so no visible bubbles) so no need for any in tank equipment.

I just ignore the need for them twinstar thingies, skimmers and wave pumps altogether.


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## Daveslaney (29 Dec 2018)

Do you not get any problems with the eheim classics of co2 collecting in the filters with diffusers on the intakes?


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## foxfish (29 Dec 2018)

Daveslaney said:


> Do you not get any problems with the eheim classics of co2 collecting in the filters with diffusers on the intakes?


That is one of the issues with this method but how would you even know?
There could be 4-5” of gas trapped in the top of the filter but if you can’t see what’s going on inside how can you tell and the other question is does it matter if there is trapped gas!
Well perhaps a PH profile would show something up, I have seen this posted before where folk can’t understand why the Ph hardly changes  overnight, it is because the filter is still dissolving trapped gas for hours after it has been switched off.
Whether that matters is yet another question......


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## Daveslaney (29 Dec 2018)

By the looks of the pics of the Ehiem 600 classic 2017 the filter canister is a light transparent green. So you should be able to see into the filter.
There are no filter baskets etc in this filter. So if co2 don't get trapped in the impeller cavity as it sounds like it doesn't,filled with bac balls or simular it could make a good co2 reactor?


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## AverageWhiteBloke (29 Dec 2018)

The biggest issue I would suggest would be the gas collecting inside the impeller housing rather than the canister body When you take the canister apart even after it has stood for ten minutes the impeller is still warm to the touch. The impeller is self cooling and lubricating in so far as it is always submerged in water. The risk being that if you get a co2 pocket in the housing you run the risk of the impeller getting hot, rattling about and wearing it down quicker. 

I haven't experienced this yet but then again I don't inject directly into the intake pipe s not all the co2 ends up in there. What I found when using reactors was you had to knock the co2 a little bit earlier than usual and off a bit earlier as they seem to retain gas longer although, that could be down to the fine mist not floating about in the tank getting inside the drop checker and making it react quicker?

Also had burping from my filter when the gas was turned up high enough even with the atomiser on the outlet. If there's enough mist floating about in the tank sooner or later quite a lot of it is going to end up in the canister especially if you have your flow set up son the end point of the outflow is the filter in take to get a swirling action.

I get round the worrying about whether it's going to damage my canister by being in a local fish keeping buy sell and swap group on Facebook. There's canister filter on there all the time for buttons  So whatever. So far though I've never damaged one by letting co2 go into the canister.  

Sent from my STH100-2 using Tapatalk


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## Daveslaney (29 Dec 2018)

I've tried it so far with my tetratec 1200 and a fluval 306 co2 just gets caught in the filter and both have Ended up coughing and burping co2 so not a good idea with these filters. But from what I can gather the Ehiem classics are just a filter canister and the pump is in the housing/casing above the canister?
Going to keep my eye out for a second hand one and give it a try I think.


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## tiger15 (30 Dec 2018)

There is reason why all commercially made reactors are installed after the canister.  Feeding CO2 into a canister can shorten the life of the impeller in several ways.  First, it can cause cavitation, explosion of micro bubbles that physically erode the impeller. https://en.wikipedia.org/wiki/Cavitation   Second,  carbonic acid is corrosive to metal parts, such as the impeller shaft.  The highest concentration out of the reactor is most corrosive.  Third,  if an air pocket is formed around the impeller, it can overheat.


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## ian_m (30 Dec 2018)

Carbonic acid is a very weak acid and will not react with metals in your filter. However CO2 does dissolve in rubber snd there have been numerous reports of rubber seals failing when exposed to CO2. Depending rubber type the rubber either melts or hardens.


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## Daveslaney (30 Dec 2018)

Aside from the burping/ coughing of the filter I would think all of the above could probably be applicable what ever way you choose to inject co2 into the water column?
The main reason I have had to change a filter is due to the priming button failing this is prob due to co2 damaging the rubber flap structure used in most of these?


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## AverageWhiteBloke (30 Dec 2018)

Possibly Dave, co2 does tend to make rubber and plastic parts quite brittle.


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## tiger15 (30 Dec 2018)

Carbonic acid may be a weak acid, but in high concentration off the reactor, and synergetic with cavitation effect and the presence of strong electrolytes (fert), can take a toll on stainless steel over time.  When the impeller or the shaft is shot, the first thing you notice is clicking noose due to out of balance rotation.

  I upgraded my gas fired hot air heating system a few years ago with a 95% efficiency furnace which recovers fugitive heat from the CO2/H2O  exhaust.  The byproduct is carbonic acid and must be discharge carefully in corrosion resistant conduit.  The installer told me that these high efficiency furnaces have more repair issues than old ones due to CO2 corrosivity and design complexity.


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## Daveslaney (30 Dec 2018)

Most impeller shafts are made of ceramic now.


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## ian_m (30 Dec 2018)

tiger15 said:


> I upgraded my gas fired hot air heating system a few years ago with a 95% efficiency furnace which recovers fugitive heat from the CO2/H2O  exhaust.  The byproduct is carbonic acid and must be discharge carefully in corrosion resistant conduit.  The installer told me that these high efficiency furnaces have more repair issues than old ones due to CO2 corrosivity and design complexity.


Absolutely nothing to do with carbonic acid which only exists in solution, and cold/cooler one at that. Boiler flue gasses are contaminated with hydrochloric, nitrous and nitric acid and sulphuric acid which are many many many times stronger acids than highly unstable carbonic acid, which is why quality stainless and suitable plastics must be used. Carbonic acid attacking metals...unlikely in concentrations and pressure we meet.


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## tiger15 (30 Dec 2018)

ian_m said:


> Absolutely nothing to do with carbonic acid which only exists in solution, and cold/cooler one at that. Boiler flue gasses are contaminated with hydrochloric, nitrous and nitric acid and sulphuric acid which are many many many times stronger acids than highly unstable carbonic acid, which is why quality stainless and suitable plastics must be used. Carbonic acid attacking metals...unlikely in concentrations and pressure we meet.


What are you talking about boiler flue gas.  I am on natural gas, which is methane.  CH4 + O2 = CO2 + 2H2O
In old furnace, CO2 and steam exhaust through the chimney.  In high efficiency furnace, the heat of the exhaust gas is recovered resulting in condensation of carbonic acid. The exhaust gas runs through stainless steel coil for heat exchange, and over time, the coil is ruined and needs to be replaced.


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## Hades (31 Dec 2018)

Daveslaney said:


> Do you not get any problems with the eheim classics of co2 collecting in the filters with diffusers on the intakes?



Nothing dramatic.
I run quite a high BPS on both. It happens that the filters burp once or twice by the end of the day but rather sporadic and small burps.
I lied before (more being lazy): it's one eheim classic and one eheim Pro3 and not two classics.
I noticed when the classic burbs, it spits the co2 out in very fine bubbles, finer mist then the atomiser itself.
When the pro3 burbs it produces a couple of big bubbles.

The eheim is indeed transparent and i checked the top of cannister a few times when i started this method to see it there was any gas build up during burping.
Funny enough there was not one big bubble of trapped gas under the pump during the burping but a continuous stream of bigger bubbles came out of the last filterbasket, those bubbles moved fast through the top layer (between basket and pump) and got sucked up in the pump...
So if a co2-pocket was formed it appeared to be in the media basket and not at the top of the canister...



ian_m said:


> However CO2 does dissolve in rubber snd there have been numerous reports of rubber seals failing when exposed to CO2. Depending rubber type the rubber either melts or hardens.



I'm not doing it long enough yet to evaluate any possible impact on filter/seals/parts.

Am a bit wary now anyhow...
Trend set...
I guess 2019 will be riddled with stress, sweat and nightmares from the word "go"...


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## AverageWhiteBloke (2 Jan 2019)

Anything that increases the distance between the impeller housing and injection point of the gas will reduce the chances of a buildup I would say. Probably worthwhile putting the inline diffuser as far up the inlet pipe as possible so it has the full length of the tubing to travel. @Zeus. also uses one of the EPS flow through canisters which doesn't have any moving parts other than the pipe connectors. By the time the mist gets down the tubing and the extra canister I don't think there would be much gas left to get into the housing of the main canister filter. The worry there though would be how much this restricts the flow.


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