# Should I have surface agitation with co2 injection ?



## drodgers (23 Oct 2014)

As the title states should I let the turn over from the filter oxygenate the water if it does, or can i use a pump at the surface to create ripples.
I don't want to out gas my co2.
Im starting to think my dissolved o2 is low because my plants don't pearl and my angels spend a bit of time at the surface .
My surface has a film on top with excess co2 bubbles trapped underneath it/i use a reactor the bubbles are excess.


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## ceg4048 (24 Oct 2014)

drodgers said:


> Im starting to think my dissolved o2 is low because my plants don't pearl and my angels spend a bit of time at the surface .


Instead, you should start to think that your flow/distribution scheme is inadequate.

Cheers,


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## Rıza Sırman (24 Oct 2014)

You may position your filter outlet near to the water surface. The movement on the water surface will break the film and let your water oxygenate.
Also you may use an ait pump to break this surface. You may use air pump at nights. Because plants produce CO2 at nights too. This will balance the CO2/O2 ratio of the tank.


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## drodgers (24 Oct 2014)

ceg4048 said:


> Instead, you should start to think that your flow/distribution scheme is inadequate.
> 
> Cheers,


Its not i can you can be assured that!  I have my spray bar and the rest of my outlets below the surface.
Its seems you have a canned message for every question here  my question is 
*Should I have surface agitation with co2 injection* ... I've been concentrating on not out gassing the tank and am thinking is it needed or should not bother with the surface tension


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## foxfish (24 Oct 2014)

Perhaps you could try & tilt the spray bar up a little, enough to agitate the surface is the norm.
You need to experiment as there are not always universal answers available.


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## ian_m (24 Oct 2014)

drodgers said:


> Im starting to think my dissolved o2 is low because my plants don't pearl


What is the connection between low O2 and lack of pearling ????

O2 and CO2 dissolve independently of each other (Henry's law), adding CO2 doesn't effect the amount of O2 in the water. Lack of O2 has nothing to do with lack of pearling 

Lack of pearling can be caused by many things, main one as has been mentioned many many many times is "Instead, you should start to think that your flow/distribution scheme is inadequate" also complete lack of CO2, also lack of light, also type of plant, some never pearl and also too much flow so that O2 dissolves before it has a chance to form a bubble.


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## ceg4048 (24 Oct 2014)

drodgers said:


> Its not i can you can be assured that!


This is why I have a canned message. This statement is the worst possible mindset and everybody thinks this.

These are the symptoms of poor Flow and distribution:


drodgers said:


> my angels spend a bit of time at the surface





drodgers said:


> My surface has a film on top


What this means is that the fish are suffering hypercapnia while the plants are suffering CO2 deficiency. That only happens with poor distribution so you always need to review the configuration. Since we can't see what you are doing we are forced to guess based on the evidence in what folks write.

Thinking that you have low dissolved oxygen just because plants are not pearling is one of the worst misdiagnoses you can make,  so immediately you are off in the wrong direction and are asking the wrong questions. Trying to solve a problem that does not exist can sometimes cause bigger problems.

When we can see a diagram or  image of how the distribution scheme is configured, when we have an idea of your pH profile and when we can see what the KH, temperature and gas dissolution methods are then we will be able to determine a path forward.

Cheers,


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## ian_m (24 Oct 2014)

Your drop checker says ???


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## drodgers (24 Oct 2014)

ian_m said:


> Your drop checker says ???


perfect 30 ppm ,



ian_m said:


> What is the connection between low O2 and lack of pearling ????


submerged plants remove oxygen from the water for respiration.



ian_m said:


> Your drop checker says ???


pretty green   1.2 ph drop i should be 30ppm


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## drodgers (24 Oct 2014)

ceg4048 said:


> These are the symptoms of poor Flow and distribution:


it would be if i wasnt keeping a 5 foot spray bar 12 inches below the surface and all my outputs the same in fact i removed a filter to decrease flow .
my question is still the same does breaking the tension out gas the co2 or not enough to worry?


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## parotet (24 Oct 2014)

drodgers said:


> it would be if i wasnt keeping a 5 foot spray bar 12 inches below the surface and all my outputs the same in fact i removed a filter to decrease flow .
> my question is still the same does breaking the tension out gas the co2 or not enough to worry?


Sorry, 12 inches?... This is 25 cm below the surface, thus near the bottom.
If it is not a typing mistake (you probably mean 1.2 inches) this is not definitely the place to put your spraybar which has to be 1 inch below the surface. The point of placing the spraybar in this position is to let the jets hit the front glass and then let the flow go down to the bottom and cross the whole tank reaching finally the rear glass and going up again, creating a perfect circular flow.

I'm also a bit confused when you mention 'in fact I removed a filter to decrease flow'... Why do you want to decrease flow. I guess you have flow problems, s removing a filter won't help. Sorry maybe it is my misunderstanding.

Regarding your question, every disturbance of the surface will degas the water column (raising a lily pipe, rippling the surface, etc.) but this is not bad if you just ripple slightly the surface because this will let you have stable levels of CO2 during the day. It will also be useful to get rid of the film surface. There was an old thread explaining this. Google ph profile ukaps and you will find it. Another excellent reading is this one

http://www.prirodni-akvarium.cz/en/index.php?id=en_co2ph

Check the different oh profiles in different situations.


Jordi


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## X3NiTH (24 Oct 2014)

Yes it out gasses co2 but you can increase the co2 injection rate to counteract this. Finding the balance point between injection rate and ejection rate can be a challenge.


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## ian_m (24 Oct 2014)

drodgers said:


> submerged plants remove oxygen from the water for respiration.


??? Only at night. During the day they add oxygen to the water.


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## drodgers (24 Oct 2014)

X3NiTH said:


> Yes it out gasses co2 but you can increase the co2 injection rate to counteract this. Finding the balance point between injection rate and ejection rate can be a challenge.


that what i was thinking i directed a water jet at the surface and increased my bubble count.
thanks!



parotet said:


> Sorry, 12 inches?... This is 25 cm below the surface, thus near the bottom.


LOl i keep forgetting to add that i have 125 gallon tanks in this tank 12 inches is only mid way.



parotet said:


> I'm also a bit confused when you mention 'in fact I removed a filter to decrease flow


big tank lots of filter and water jets ...

I apologize for not including my tank sizes and equipment theres a bit of difference here in Canada and your tanks.
ill add it to my signature once im home.


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## foxfish (24 Oct 2014)

OK, well I think you might have a flow issue?
What we try to achieve is to move the whole tank volume in a certain way, so if you place the spray bar near the surface, pointing just below the opposite side (front pane) you will hopefully get a continuous rolling of the water column.
A nice circular movement within the tank... the spray bar is situated just below the surface at the rear & the linear flow will cause the overall movement of the volume  to circulate.


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## drodgers (24 Oct 2014)

foxfish said:


> OK, well I think you might have a flow issue?
> What we try to achieve is to move the whole tank volume in a certain way, so if you place the spray bar near the surface, pointing just below the opposite side (front pane) you will hopefully get a continuous rolling of the water column.
> A nice circular movement within the tank... the spray bar is situated just below the surface at the rear & the linear flow will cause the overall movement of the volume  to circulate.


I agree im off to the depot to find a better fitting so i can raise my spray bar ...
Thanks also just received my 8k metal halide bulbs in the post so my tank has amazing light now


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## drodgers (25 Oct 2014)

Really bad video but 45 minutes after starting my hqi lights every plant starting pearling like mad.


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## Martin in Holland (25 Oct 2014)

IMO pearling does not mean that you have enough CO2/distribution in the tank. It only means you force the plants to pearl with high light and they will pearl untill the have no more energy left in them which ends up to become melting plants, this will than give more scum on top of your water.


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## Jaap (25 Oct 2014)

Just my 2 cents....at some point my aquarium plants were really unhealthy and not growing....I had to increase the co2 becuase the plants were melting...however the plants were melting because of very low light...instead I increased the co2 alot! The plants were slightly pearling....they had small oxygen bubbles on the leaves...so they were pearling in a sense but they were completely unhealthy and not growing because the light levels were around 5 micromols...


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## drodgers (25 Oct 2014)

Jaap said:


> .so they were pearling in a sense but they were completely unhealthy and not growing


I have a decaying leaves on the bottom of newly planted stem plants that are pearling so i can see how that can happen.


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## sciencefiction (26 Oct 2014)

Plants can pearl when they are unhealthy and can also pearl in a low tech tank too. So not much to do with high CO2 levels.
I thought plants pearl when the tank reaches O2 saturation point but I could be wrong. Either way it's got to do with O2 levels in my opinion.
If it's a plant only tank, I wouldn't worry about surface movement that much.  But in a fish tank the consumption of O2 is higher and as already mentioned, O2 and CO2 levels are independent from each other. Outgassing some CO2 via surface movement will compensate for bringing in some O2 instead.  Fish gasp at the surface when CO2 is too high for the particular species of fish.  Low O2 levels will more than likely cause unexplained fish deaths and disease outbreaks, and also anaerobic substrates, resulting in poor plant health.
So in my opinion, one should be concerned about O2 as much as CO2 and get their surface moving on the cost of losing some of the injected CO2.


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## drodgers (26 Oct 2014)

Problem fixed I corrected my spray bar height and the film is gone I also moved my 2 fans to the far corners as a result i have good rolling forward circulation.
I cleaned up any debris and did 2x 50% water changes.
Tank is sparkling clean and pearling with just my t5 light (I moved the HQI back to my other tank to bright)
Thanks for the help guys!!


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