# How much CO2?



## Daximus (Oct 19, 2011)

The pressure coming out of the tank is irrelevant. You will need enough pressure to push the Co2 though whatever method of diffuser you choose, but other than that pressure isn't a concern. 

Flow is. The way most of us around here measure flow is by b/p/s (bubbles per second) as read through a bubble counter. This is not an exact science, but it's fairly accurate and affordable. That said, b/p/s can vary from tank to tank, there are just too many variables to make any blanket statements like "you should be running 2 b/p/s to achieve 30 ppm Co2 in a 10 gallon tank". This wont work.

However, we can ball park these things to an extent. I would start at 1/2 b/p/s (30 bubbles in a minute) and see where that puts you once your drop checker gets in. Alternatively, you can watch the livestock as an indicator of Co2 levels...if they start flopping around near the top of the tank you are likely adding way too much. 

This process will tank patience and time and the results/settings will be unique to your particular setup.


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## AndreyT (Apr 28, 2011)

Cannonbolt said:


> Setting up my first pressurized system! :bounce: I have a 10 gallon tank, how many PSI do I want coming out of the CO2 tank to give me the desired ppm in the water (I believe 30 ppm is appropriate from what I've read)?


No one knows "how may psi" you will need. It depends on many factors, including the resistive properties of the specific diffuser you are going to use. For this reason nobody tries to measure it through "psi". 

The simplest and most practical method of measuring the amount of CO2 you _send_ to your tank is _bubbles_. Install a bubble counter in your system and control the amount of CO2 by counting the number of bubbles per second. The fine adjustment is performed with a needle valve, not by adjusting the working pressure on the regulator.

The amount of bubbles you'll have to send to your tank to achieve the desired ppm levels will also depend on your CO2 efficiency, i.e. on how well the CO2 dissolves in your setup (depends on the diffusing method) and how well the CO2 stays in the water after being dissolved (depends on the amount of circulation and surface agitation you have in your tank). 

In other words, there quite a few variables involved here. There's no way to give you any exact numbers in advance, be that "psi" or "bubbles" or anything else. Start your system, see what it does (by using your drop checker), adjust as necessary, repeat.

As for the working pressure (i.e. psi), all you need is to have the working pressure that is sufficient to drive your diffuser. Some diffusers (e.g. atomizers) require higher pressure to work properly.


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## Cannonbolt (Sep 13, 2007)

Thanks for the replies. I will start with 30 bubbles in one minute and tweak from there.


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## nokturnalkid (Apr 3, 2007)

Remember, only adjust when you are able to actually watch the tank for a few hours. You don't want to adjust, then go somewhere for a few hours, then find all your fish gasping or already dead just beacause you raised the your bubble rate up a tad


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## Aquaticfan (Oct 30, 2011)

Cannonbolt said:


> Thanks for the replies. I will start with 30 bubbles in one minute and tweak from there.


That would be VERY low amount. 

A good starting point is 1bps. And like said. do the adjustments when you can spend the day with it.


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## Bettatail (Feb 12, 2009)

One thing I must mention, setting the right bubble rate depends on many factors, and every tank is different.

and a big bubble is 8 times more volume than another bubble that half of the diameter.
1 big bubble = 8 small(half diameter) bubbles.

put different type of bubble counters inline(in series) you will see the big difference in bubble rate since different size of bubbles.


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## rstampa (Jan 29, 2017)

When you increase your bubbles count, only increase 1 or 2 bubbles at a time. If you don't what to wait 2 hrs for a drop check reading, you can check you PH. If you want a accurate PH reading. Don't use the paper strip type tester. They are the less accurate. Use the liquid or digital tester.


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## GrampsGrunge (Jun 18, 2012)

The Krib usenet archives has some good articles on basic planted tank water chemistry. You will want to get a GH and KH test kit and check your KH before checking your pH to estimate the levels of CO2 present.

[The Krib] CO2 & Water Hardness


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## stussy28 (Mar 17, 2016)

I've been wondering, if I have a working pressure of 30psi for my reactor, but a needle valve reduces it, then is my reactor getting the full 30psi it requires to properly work?


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