Talk Me Through Bubble Counters

[daizeUK]

I understand why I would need a drop checker and I'm just trying to wrap my head around bubble counters now.  What are they useful for and how do you know how many bps is the right number?
 
 

 

[KirkyArcher]

Well DaizeUK I use my bubble counter in sync with my JBL Co2 permanent test (Drop check) if the liquid remains blue after two hours of running the Co2 I'm not dosing enough so I increase the bpm count, if it goes beyond the recommended 20mg/l and the test liquid becomes yellow coloured there is too much Co2 in the water so the bpm requires reducing, You can also use the drop check to time the running period of your Co2 so that the amount of Co2 level has peaked (turned green) for when the lights are due to come on and like wise turn it off so that the Co2 is almost depleted just as the lights are due to turn off. I intend to place my ceramic diffuser directly under the intake strainer at the weekend to further enhance the absorption into the water, which no doubt will require further adjustment of my bpm.

 

[levahe]

All a bubble counter is used for is a visual aid to help you adjust how much gas you are injecting. Its not used as an actual measurement device. The drop checker is what you will be relying on to measure how much gas is dissolved in the water.

For instance if your drop cchecker is dark green and you want to increase the amount of gas, you turn the needle valve and see the bubble rate increase slightly, you know that you have increased the gas. If you didn't have the bubble counter you would be wondering if the turn you made on the needle valve had any effect on the flow of gas.

I hope this helps

 

[daizeUK]

Thanks for the replies, that makes sense.
Can you not use the pressure gauge on the regulator to tell you the same thing, or is it just not precise enough?

 

[levahe]

No, all that does it tell you how much pressure is in the tank, and if its a dual gauge it also tells you the working pressure.
The role of the regulator is to rweduce the extremely high pressure inside the gas bottle to a more useable pressure. The pressure in the gas bottle will be around 800psi (55bar), and the regulator will bring that down to somewhere around 30psi (2bar) about the same as the air pressure in your car tyre.

 

[daizeUK]

Thanks.  So as you adjust the needle valve does this have a noticeable effect on the working pressure?

 

[levahe]

No, the working pressure stays the same until the gas bottle runs out *. The needle valve (tap) is placed after the gauges so it doesn't control the pressure of the gas, it only controls the flow of gas. Just like your bath tap the water in the pipe is always a set pressure, but the tap controls how fast it comes out


* unless its an adjustable pressure regulator

High pressure in bottle > regulator > lower pressure > needle valve > bubble counter > diffuser

 

[daizeUK]

Thanks for explaining that!   The tap analogy really helped me grasp the difference between pressure and flow output.

 

[levahe]

I should have explained it properly to begin with XD, but once you have all the co2 equipment in front of you and get to set it up and experiment it all becomes clear. Its difficult to visualise it without getting some hands on experience

 

[daizeUK]

Evidently I didn't really understand what the regulator was doing!  I'm not very good with the concept of pressure but I think I'm getting clearer now.
 
If the regulator is reducing pressure down to 2 bar, does this mean that the CO2 pressure in the tubes is also 2 bar or does this output pressure depend on how much gas the needle valve is letting through?

 

[levahe]

The pressure in the tubes could reach a maximum of 2 bar, depending on what the resistance is at the end of the tube. If you have a diffuser that requires 1bar of pressure to work the pressure will only reach 1 bar. The pressure will build up until it reaches 1bar then starts coming out the diffuser and then stays at 1bar in the tubes.
If you totally shut off the end of the tube the pressure will only reach a maximum of 2bar due to that being the working pressure of the regulator.

Regardless of how fast or slow you are letting the gas through the needle valve, it can only ever reach a maximum pressure of 2bar

 

[daizeUK]

Makes sense thanks very much!