# co2 bpm?



## ovenmit331 (Mar 27, 2007)

so i bought this: http://www.drsfostersmith.com/Product/Prod_Display.cfm?pcatid=8981&N=2004+113779 









not too expensive. bought it because it looks a TON better than a gatorade bottle and came with the bubble counter diffuser thing and i'm gonna just re-use the canister for DIY CO2 later.

my question is how many bubbles per minute should i have? the bubbles that come out are nearly gone when they get to the top and if they're not they get sucked through a waterpump and through a UV system.

right now it's at about.... 20 bubbles per minute. but it's not adjustable. and the fish seem fine. no gasping for air or anything.


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## bigstick120 (May 23, 2005)

What size tank are you using it on? Test your PH and KH to get your CO2 reading


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## ovenmit331 (Mar 27, 2007)

30gallon hex tank. i'll have to get a kh test kit from the LFS/petsmart during lunch. any brand to recommend?


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## Wasserpest (Jun 12, 2003)

While it looks fancier, the volume of solution in that little container will not supply enough CO2 for your 30gal tank. :icon_sad:


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## ovenmit331 (Mar 27, 2007)

Wasserpest said:


> While it looks fancier, the volume of solution in that little container will not supply enough CO2 for your 30gal tank. :icon_sad:


even though i'm getting 20bpm dissolved into the water?


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## Wasserpest (Jun 12, 2003)

Well I shouldn't make statements like that...

Theoretically, under very special circumstances, it might be enough :tongue: 

If you tank is

- low to medium light (1.5-2 W/gal)
- has no surface agitation, but still sufficient water circulation
- indeed 100% of the CO2 is dissolved

then it might get you to decent levels.

Most likely though, a little container like this, on an average 30gal tank, will not do much. For a high light tank... welcome to algae land! :smile:


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## ovenmit331 (Mar 27, 2007)

Wasserpest said:


> Well I shouldn't make statements like that...
> 
> Theoretically, under very special circumstances, it might be enough :tongue:
> 
> ...


it's at 2.4 wpg. (want more but not sure how to get it)
not much surface agitation at all

it might not be enough, but it's better than none, right?

what's the best way to measure co2?

24hr ph drop or ph/kh chart?


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## Wasserpest (Jun 12, 2003)

Both will give you a ballpark idea, as long as your pH test is decent.


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## ovenmit331 (Mar 27, 2007)

pH is 7.8 and kH is 14º which means co2 is 6.7ppm... right?


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## Wasserpest (Jun 12, 2003)

Right... so just a bit above equilibrium, as expected. Try to get it over 10ppm at least, that would be better than nothing, 20 would be pretty optimum, and 30 would put your plants on steroids. :smile:


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## Left C (Nov 15, 2003)

Hi ovenmit331

Would you want to add a second Hagen kit to your aquarium?


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## ovenmit331 (Mar 27, 2007)

Left C said:


> Hi ovenmit331
> 
> Would you want to add a second Hagen kit to your aquarium?


i had that thought... why?


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## ovenmit331 (Mar 27, 2007)

Wasserpest said:


> Right... so just a bit above equilibrium, as expected. Try to get it over 10ppm at least, that would be better than nothing, 20 would be pretty optimum, and 30 would put your plants on steroids. :smile:


when i tested it last the water level had dropped and had quite a bit of surface agitation. and the bubble ladder wasn't under the water pump intake for my uv filter so i'm gonna go back and test it again. see if both of those made any difference... 

also, if the bubble that don't dissolve and come out the top are run through the intake of a HOB filter, would that do any good? or would all the co2 that could be dissolved in that process be lost through the filter and return?


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## Wasserpest (Jun 12, 2003)

ovenmit331 said:


> also, if the bubble that don't dissolve and come out the top are run through the intake of a HOB filter, would that do any good? or would all the co2 that could be dissolved in that process be lost through the filter and return?


In my experience, once the bubble has run up the ladder all the way, there is not much/any CO2 left in it. CO2 dissolves very quickly, and if you have bubbles escaping on the top most likely they are simply air. Remember when you set up a DIY bottle, initially you have some air in it, and until it gets all purged you will keep seeing bubbles that don't dissolve completely.

Short answer - no, catching these bubbles and running them through another HOB filter will not raise CO2 levels.


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## Left C (Nov 15, 2003)

ovenmit331 said:


> i had that thought... why?


I have two reasons.

1) The Hagen is only rated for use with aquariums up to 20 gallons and your aquarium is 30 gallons.

2) I had to use 2 of them on a 15 gallon tank to get the CO2 level that I wanted.


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## ovenmit331 (Mar 27, 2007)

Left C said:


> I have two reasons.
> 
> 1) The Hagen is only rated for use with aquariums up to 20 gallons and your aquarium is 30 gallons.
> 
> 2) I had to use 2 of them on a 15 gallon tank to get the CO2 level that I wanted.


i may just do that. i found a local store that sells em for like $16


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