Co2 - How Much Is Too Much?

mlash

Member
I have been running my co2 at just over 1 bps and the indicator was a darker greenish color. I have since increased to 2 bps and now the indicator is much lighter greenish looking like it wouldn't take much more to turn it yellow. Does anyone have any thoughts as to which is better, greenish towards blue or greenish towards yellow?
 

-Mak-

Member
More towards a lime green is what experienced users do, but a darker green will have a ton of benefit too. It may be more prone to algae issues if it fluctuates between the two. If you have a lot of surface agitation and therefore dissolved oxygen, your livestock will be much more forgiving of higher CO2
 

Chanyi

Member
Use a pH drop method instead of relying on a drop checker (drop checkers are only good for a quick, un-accurate visual of CO2 levels).

Measure pH of water with no CO2 dissolved at all.
Measure again when CO2 is at it's max, within 1 hour of it turning off for the day.

The difference should be a full 1.0 drop up to a 1.4 drop in pH. If you are achieving over a 1.0 drop, you are at optimal levels. Can I ask what size tank this is on? My 25 gallon tank is nearing 5 bubble per second. I am dropping pH from 7.1 down to 5.9. I have plenty of surface agitation, and no gasping fish. If your fish are gasping at the surface, that is too much CO2. Gradually work up to those levels. Drop checker is a super light green, more yellow than green.
 
  • Thread Starter

mlash

Member
Chanyi said:
Use a pH drop method instead of relying on a drop checker (drop checkers are only good for a quick, un-accurate visual of CO2 levels).

Measure pH of water with no CO2 dissolved at all.
Measure again when CO2 is at it's max, within 1 hour of it turning off for the day.

The difference should be a full 1.0 drop up to a 1.4 drop in pH. If you are achieving over a 1.0 drop, you are at optimal levels. Can I ask what size tank this is on? My 25 gallon tank is nearing 5 bubble per second. I am dropping pH from 7.1 down to 5.9. I have plenty of surface agitation, and no gasping fish. If your fish are gasping at the surface, that is too much CO2. Gradually work up to those levels. Drop checker is a super light green, more yellow than green.
My tank is a 20gal long (open top). I will measure tonight to see how much the pH is dropping. I have plenty of surface agitation but I don't use an air pump. My fish aren't gasping yet though.

Are you using an in-tank, in-line or a reactor to inject your co2? Currently I am using an in-tank but I did just get an in-line diffuser, I just haven't installed on my canister filter yet.

Thanks for the advise. I will post the results after I measure, I'm sure I can squeeze some more bubbles in there somewhere.
 

Chanyi

Member
mlash said:
My tank is a 20gal long (open top). I will measure tonight to see how much the pH is dropping. I have plenty of surface agitation but I don't use an air pump. My fish aren't gasping yet though.

Are you using an in-tank, in-line or a reactor to inject your co2? Currently I am using an in-tank but I did just get an in-line diffuser, I just haven't installed on my canister filter yet.

Thanks for the advise. I will post the results after I measure, I'm sure I can squeeze some more bubbles in there somewhere.
I use an inline reactor:

KAF2LPP.jpg

3" pipe x 22" tall. Bubbles per second is around 4.75 - 5 (counted using a metronome matching the beats per minute to the sound of bubbles entering the reactor and then dividing by 60 seconds to yield a bubble per second value). A Dwwyer rma151ssv flow meter is actually ideal - coupled with a pH controller to ensure a perfect pH drop from using CO2 (I don't use this unfortunately).

The important thing with CO2 is consistency. Plants will adapt their inner working to best perform at a given CO2 level (when actively growing = up taking CO2). SO having CO2 stay consistent at a given level is the most beneficial. Interrupting the plants growth to deal with inconstant CO2 is asking for trouble, especially when running higher light or a thin margin of error with fertilizers.

Increased surface agitation is key as well - ensure max oxygen AND CO2 levels are present in the tank.
 
  • Thread Starter

mlash

Member
Chanyi said:
I use an inline reactor:

KAF2LPP.jpg

3" pipe x 22" tall. Bubbles per second is around 4.75 - 5 (counted using a metronome matching the beats per minute to the sound of bubbles entering the reactor and then dividing by 60 seconds to yield a bubble per second value). A Dwwyer rma151ssv flow meter is actually ideal - coupled with a pH controller to ensure a perfect pH drop from using CO2 (I don't use this unfortunately).

The important thing with CO2 is consistency. Plants will adapt their inner working to best perform at a given CO2 level (when actively growing = up taking CO2). SO having CO2 stay consistent at a given level is the most beneficial. Interrupting the plants growth to deal with inconstant CO2 is asking for trouble, especially when running higher light or a thin margin of error with fertilizers.

Increased surface agitation is key as well - ensure max oxygen AND CO2 levels are present in the tank.
Thanks for sharing, very nice. I will eventually have to build me one of these. Right now I'm just trying to get all the specifics to the big picture so to speak. Thanks for all the info it is very helpful.
 

Wraithen

Member
mlash said:
Thanks for sharing, very nice. I will eventually have to build me one of these. Right now I'm just trying to get all the specifics to the big picture so to speak. Thanks for all the info it is very helpful.
I just got set up and running myself. I have a pretty high kh since my ph starts at 8.2 I got all the way down to about 6.6 and it only turned my drop checker a few shades darker than lime green. Even with that amount of co2, my fish had zero issues. I have a hob that drops about an inch into the water and my spray bar causes ripples halfway across my 6 foot tank. As hinted at earlier, you can push more co2 if you push more o2. Surface agitation is key. I won't be running my co2 quite that hard from here on in, but wanted to give you an idea. There are plenty of experienced guys running yellow drop checkers with zero issues because they have a lot of gas exchange and surface agitation. Co2 and o2 aren't inherently mutually exclusive. But you do have to do it right to avoid gassing fish.
 
  • Thread Starter

mlash

Member
Wraithen said:
I just got set up and running myself. I have a pretty high kh since my ph starts at 8.2 I got all the way down to about 6.6 and it only turned my drop checker a few shades darker than lime green. Even with that amount of co2, my fish had zero issues. I have a hob that drops about an inch into the water and my spray bar causes ripples halfway across my 6 foot tank. As hinted at earlier, you can push more co2 if you push more o2. Surface agitation is key. I won't be running my co2 quite that hard from here on in, but wanted to give you an idea. There are plenty of experienced guys running yellow drop checkers with zero issues because they have a lot of gas exchange and surface agitation. Co2 and o2 aren't inherently mutually exclusive. But you do have to do it right to avoid gassing fish.
Thanks for the info. Yeah, I checked my pH tonight about an hour before the co2 shut down and my pH only dropped from 6.8 to 6.3. I'm going to bump it up a little and see if I can get it down a little more.
 
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