martinmin Posted August 5 Share Posted August 5 (edited) Let's say I have a 5-gallon planted fish tank and I am using this attached bubble counter to measure CO2 rate. What's the normal rate I should use in injecting CO2 to tank? ChatGPT says 1 bubble 1 second and that seems very fast. Does the '1 bubble' the same as the one drop in this bubble counter? I usually control it as 1 drop every 15 seconds, but I actually what's the ideal rate of injection. Please see attached. Edited August 5 by martinmin Link to comment Share on other sites More sharing options...
Mmiller2001 Posted August 5 Share Posted August 5 A bubble counter is literally the single most useless measure of CO2 ever created. It provides no information other than some amount of CO2 is flowing through the regulator. The best method to measure CO2 is to take a pH measure when the aquarium water has reached atmospheric equilibrium and then take a measure of pH after CO2 has been introduced into the water. You will be looking for a negative pH drop of 1 to 1.5. Link to comment Share on other sites More sharing options...
martinmin Posted August 5 Author Share Posted August 5 On 8/4/2024 at 9:46 PM, Mmiller2001 said: A bubble counter is literally the single most useless measure of CO2 ever created. It provides no information other than some amount of CO2 is flowing through the regulator. The best method to measure CO2 is to take a pH measure when the aquarium water has reached atmospheric equilibrium and then take a measure of pH after CO2 has been introduced into the water. You will be looking for a negative pH drop of 1 to 1.5. What's is atmospheric equilibrium? So I need to take a measure of PH before Co2 injection, and another measure after CO2 injection? In between, how long should I wait for it to take effect? Do you use test strip paper or API liquid test kit? In both cases, I feel those readings won't be exact, because basically you just eyeball the color and compare it with the 'standard' readings. Personally, I find it very in-precise to even get an accurate measure of those parameters. So a drop of 1-1.5 PH drop seems hard. Link to comment Share on other sites More sharing options...
Pepere Posted August 5 Share Posted August 5 Determining the bubble count you need is impossible. For one different styles of bubble counters will yield different counts… But it is worse than that. Even if you have a device that precisely told you how many liters per minute you were injecting, every tank and setup will reach a different co2 level with that volume of co2 being injected… taking a sample of tank water and leaving it exposed to atmosphere for 24 hours, preferably in an area with low ambient co2 levels gives you a baseline of the ph level in your tank.. I put it in my basement when I am running the AC with the windows closed as the co2 levels down there are around 600 ppm and my living space with my breathing is around 1200 ppm with the windows closed… then you take a series of ph tests as the co2 is running in the tank. Once the ph drops to its lowest level and stabilizes. Ie it stops dropping that is where the co2 levels in the tank reaches equilibrium. Ie the amount of co2 outgassing from the tank is equal to the amount of co2 being injected… On 8/5/2024 at 1:08 AM, martinmin said: I feel those readings won't be exact, because basically you just eyeball the color and compare it with the 'standard' readings. Personally, I find it very in-precise to even get an accurate measure of those parameters. So a drop of 1-1.5 PH drop seems hard. Yep, it is sloppy and imprecise…but by and large it gets you close enough. Note, the 1.5 ph drop is sort of the very limit of what you would want to see rather than a goal you want to initially aim for. A drop of 1 gives you a greater margin of safety… on a 5 gallon tank your bubble count rate could even be less than 1 bubble per second… In fact I would initially start it running at less until you see what the ph drop ends up looking like… Link to comment Share on other sites More sharing options...
Pepere Posted August 5 Share Posted August 5 (edited) Bear in mind, the margin for error in a 5 gallon tank are going to be very small. I can not see where I would ever be doing injected co2 in a 5 gallon tank myself… but then again, I have a hard time seeing where I would set up a 5 gallon tank myself as well. None of this is intended to be critical or dismissive of a 5 gallon tank, I just cant see myself starting anything smaller than 15-20 gallons personally… Edited August 5 by Pepere Link to comment Share on other sites More sharing options...
Mmiller2001 Posted August 5 Share Posted August 5 Everything @Pepere says but will add a precaution to keep in mind. When you take a sample, set it out for 24 hours, you will have some evaporation of the sample. This will change the KH value of the sample and alter the degassed pH and will not necessarily represent the degassed pH of the aquarium. I would take a jar, with a tight fitting lid and shake the sample for 15 minutes. Every 5 minutes, open the jar and expose it the atmosphere. Doing this out side is ideal. After the 15 minutes, pH the sample. You can shake longer for more precision, but this will get you close enough. Link to comment Share on other sites More sharing options...
martinmin Posted August 5 Author Share Posted August 5 On 8/5/2024 at 2:40 AM, Pepere said: Determining the bubble count you need is impossible. For one different styles of bubble counters will yield different counts… But it is worse than that. Even if you have a device that precisely told you how many liters per minute you were injecting, every tank and setup will reach a different co2 level with that volume of co2 being injected… taking a sample of tank water and leaving it exposed to atmosphere for 24 hours, preferably in an area with low ambient co2 levels gives you a baseline of the ph level in your tank.. I put it in my basement when I am running the AC with the windows closed as the co2 levels down there are around 600 ppm and my living space with my breathing is around 1200 ppm with the windows closed… then you take a series of ph tests as the co2 is running in the tank. Once the ph drops to its lowest level and stabilizes. Ie it stops dropping that is where the co2 levels in the tank reaches equilibrium. Ie the amount of co2 outgassing from the tank is equal to the amount of co2 being injected… Yep, it is sloppy and imprecise…but by and large it gets you close enough. Note, the 1.5 ph drop is sort of the very limit of what you would want to see rather than a goal you want to initially aim for. A drop of 1 gives you a greater margin of safety… on a 5 gallon tank your bubble count rate could even be less than 1 bubble per second… In fact I would initially start it running at less until you see what the ph drop ends up looking like… That seems a lot to set it up. What is your tank size and how many drops do you inject per seconds, or how many seconds do you inject one bubble? I can get an idea of reference. Link to comment Share on other sites More sharing options...
Pepere Posted August 5 Share Posted August 5 On 8/5/2024 at 10:31 AM, martinmin said: That seems a lot to set it up. What is your tank size and how many drops do you inject per seconds, or how many seconds do you inject one bubble? I can get an idea of reference. It simply is not linear to tank size. I have a 29 gallon tank and use a different style bubble counter, the co2 is injected with an inline diffuser and into the tank with a spraybar that induces circular flow in the tank holding the gas in suspension in the tank.. the volume to surface area between a 5 gallon and 29 gallon is worlds apart. Truth be told I have no idea how many bubbles per second is going through the bubblecounter. I use the counter to determine if adjustment increased or decreased the flow… I then run oh tests till tank reaches equilibrium…. I also have a drop checker in the tank used mostly as a visual screening tool.. I never use the drop checker to adjust the flow rate of CO2… On a 5 gallon tank you might be happier with a CO2 bell rather than injecting via diffuser. It prevents overdosing the tank with co2… Link to comment Share on other sites More sharing options...
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