# CO2 Bubble Counter BPS - (Water vs Glycerin)



## thadius65 (Sep 15, 2006)

Ted's stupid question of the day (should start a daily sticky...):

So all the talk on this and other forums about bubbles per second/minute... I have always used water and have had very high BPS/BPM. Never seem to have enough CO2. Fish are fine, algae is TOO!

Question - when all are discusing counts, is it with water or glycerin in the bubble counter? cause it is really really different. My water BPS was 4.8-5.0 and nothing seemed impacted, fish fine, etc. Now I have glycerin in and want to know what I should start with. (leaving all as was, the bubbles were cut down by probably 2/3rds due to liquid viscosity.

I realize this is not the way to tell "how much" CO2... but looking for a rough idea.

Thanks for all your help!

Ted


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## Darkblade48 (Jan 4, 2008)

I think it depends. Most people use different liquids, so when talking about "bubbles per second/minute", in reality, it is quite meaningless.


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## photoman (Mar 28, 2010)

I'll throw a third option out there. Commonly available Mineral Oil, from the drugstore is what I've been using and it seems to work really well.


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## born2lovefish (Dec 29, 2006)

photoman said:


> I'll throw a third option out there. Commonly available Mineral Oil, from the drugstore is what I've been using and it seems to work really well.


I will have to check out CVS and Walgreens for this.


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## farmhand (Jun 25, 2009)

Darkblade48 said:


> I think it depends. Most people use different liquids, so when talking about "bubbles per second/minute", in reality, it is quite meaningless.


Just checking to see if I understand this. The liquid in the counter is a variable between counters which means one counter at 2 bubbles per may be actually slower than another counter at 1 per. The counter is simply a benchmark for adjusting your own individual co2 volume. Is this correct?


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## insta (Jan 27, 2010)

Completely correct. CO2 is affected by diffusion, atmospheric gas exchange (surface ripple and HOB filters), and plant consumption. Once you have a properly-calibrated drop checker, bubbles per second is meaningless. I've actually removed mine from my CO2 loop.


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## BG1772 (Jul 2, 2009)

I recently switched from Mineral Oil back to Distilled Water. I had my BPS very high and it was actually pushing the mineral oil into the tube eventually resulting in an oil slick on the surface of my tank. 

I mainly use the bubble counter as a rough estimate at how much CO2 I am pushing through the system. My Drop Checker and Fish are my real gauge on if I have the right amount of CO2 in the tank.


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## thadius65 (Sep 15, 2006)

Are drop checkers accurate in all conditions? (high GH or KH, etc?)

Let me ask another way - Are there any situations where a drop checker is not the thing to use for accuracy?

What is a good drop checker to get?

Thanks!


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## BG1772 (Jul 2, 2009)

I'm new to Drop Checkers, but the key is the "solution" you put in it. You need to use 4dKH water. That way you have a known carbonate amount in the water that you are using for the test. There are a lot of great posts on the planted tank that can explain the drop checker better than I.

I got mine off ebay for about $8. Think it came from Hong Kong.


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## insta (Jan 27, 2010)

The solution you put into the drop checker is an artifact of other factors. CO2 will dissolve into (and out of) water quite readily. A drop checker has an air-bubble in it to promote CO2 to move from it into the solution in the checker itself. As CO2 dissolves into water, it lowers the pH. The more carbonates (kH) in the water, the more CO2 must be dissolved to cause the same drop in pH.

The drop checker solution we use is an acid-sensitive one called bromothymol blue. It turns yellow in a pH of 6.0, and blue in a pH of 7.6. It's a useful indicator for us, because it's easy to see the differences between yellow and blue. Green, in the middle of them, is what everyone shoots for. You'll often see references to "my drop checker is green" -- that's why.

So, a green solution is about pH 6.5. If the drop checker were full of distilled water, a very low CO2 concentration (just a few ppm) would drop the pH down to 6.5. While the change could be seen, the CO2 concentration wouldn't be enough to be useful. This is where the carbonate (kH) number comes from. By raising the carbonate hardness of the checker solution, we require more and more CO2 dissolved in the water to lower the pH down into the green range. 30ppm CO2 is what most aquariasts shoot for, and 4dKH solution happens to be the magic number at which the solution is pH 6.5. If you use a lower hardness solution, you'll need less CO2 to hit green. Conversely, more carbonate hardness will require more CO2.

You may find that your fish are fine at 70ppm CO2. If so, you'll want to up your reference solution to a harder one to reflect this. The same is true at 20ppm. It's not too helpful if your drop checker is yellow (or blue) all the time!

Let me know if you need any more clarification


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## farmhand (Jun 25, 2009)

insta said:


> By raising the carbonate hardness of the checker solution, we require more and more CO2 dissolved in the water to lower the pH down into the green range. 30ppm CO2 is what most aquariasts shoot for, and 4dKH solution happens to be the magic number at which the solution is pH 6.5. If you use a lower hardness solution, you'll need less CO2 to hit green. Conversely, more carbonate hardness will require more CO2.


I am a little confused if/when your tank water has a higher KH than your drop checker that you would be setting your c02 levels to KH4 and not the KH of your tank. I'm I missing something?


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## insta (Jan 27, 2010)

The CO2 concentration (in ppm) is the same in the tank as the drop-checker. If your tank and drop-checker are both at 30ppm, but your tank's kH levels are higher than the drop-checker, that just means that the drop-checker will be a lower pH. 

The drop-checkers really are no more than a realish-time pH gauge.

(clearer yet? I can't tell if I answered the question or not, please let me know if not  )


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## jargonchipmunk (Dec 8, 2008)

the Kh of your tank means nothing in this scenario. The reason for the drop checker to have 4dKh water is so that it is a reference standard at all times and doesn't rely on the tank water to be perfect. My tank, your tank, my uncle's neighbor's tank will ALWAYS register the same in a drop checker with equal ppm of Co2 in the water.


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## farmhand (Jun 25, 2009)

insta said:


> The CO2 concentration (in ppm) is the same in the tank as the drop-checker. If your tank and drop-checker are both at 30ppm, but your tank's kH levels are higher than the drop-checker, that just means that the drop-checker will be a lower pH.
> 
> The drop-checkers really are no more than a realish-time pH gauge.


So;
1. CO2 levels effects PH
2. CO2 levels DO NOT effect KH or the inverse.
???


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## insta (Jan 27, 2010)

Ayup. 

A higher kH means that the pH swing effected by *any* acid or base is reduced. CO2 dissolved in water produces carbonic acid, which is what the drop-checker solution is really telling you. You could turn your drop-checker solution green if you wanted to by adding drops of vinegar (a weak acid).

I am more than happy to go over this as often as you need. I love for people to understand the science behind why the world around them works the way it does in seemingly small things like this.


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## thadius65 (Sep 15, 2006)

So are there any drop checkers available (in stock) in the states? Don't like waiting 3-4 weeks for a hong kong delivery. Looking by googling with no success.


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## insta (Jan 27, 2010)

Make one with some acrylic tubing.


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## Darkblade48 (Jan 4, 2008)

farmhand said:


> Just checking to see if I understand this. The liquid in the counter is a variable between counters which means one counter at 2 bubbles per may be actually slower than another counter at 1 per. The counter is simply a benchmark for adjusting your own individual co2 volume. Is this correct?


This is correct. The bubble counter, at that point, would simply serve as a easy visual reference to ensure that your CO2 is flowing.



thadius65 said:


> So are there any drop checkers available (in stock) in the states? Don't like waiting 3-4 weeks for a hong kong delivery. Looking by googling with no success.


You can always DIY one yourself. I wrote up a guide, that can be found here:

http://www.plantedtank.net/forums/general-planted-tank-discussion/107303-newbie-setup.html#6


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