Running Co2 Injection And Air Pump At The Same Time

[BlackRubyBarber]

I recently set up a 20-gallon high tank with nine Black Ruby Barbs and several live plants. I was wondering if I should be running my air pump while injecting Co2 simultaneously. 

[Pepere]

You dont have to run your air pump, but you should have some means of surface agitation when you run co2.  
 

Gas exchange form an airstone primarily works for the surface agitation it induces.  
 

if you dont have any surface agitation, you necessarily have to run much lower levels of co2.  While that might at first blush seem to be a good idea, lowering your co2 cost, bear in mind that the cost of the actual co2 is really not that high…. And, the time before you reach equilibrium where water co2 absorption is the same as loss from gas exchange will be much longer, meaning longe periods of time with low levels of co2.

 

with surface agitation and hence increased gas exchange you run higher co2 injection and get up to your target levels quicker, but it doesnt exceed the target level because you are injecting at the level it off gasses…. Ie it gets up to that equilibrium level faster and stays stable through the day.

 

for myself, I run air stones in all of my tanks to run undergravel filter plates.   I spend about $10.00 a month on co2 running two 29 gallon tanks and a 20 high at around 30 ppm.

[BlackRubyBarber]

On 4/27/2023 at 8:49 AM, Pepere said:

with surface agitation and hence increased gas exchange you run higher co2 injection and get up to your target levels quicker, but it doesnt exceed the target level because you are injecting at the level it off gasses…. Ie it gets up to that equilibrium level faster and stays stable through the day.

for myself, I run air stones in all of my tanks to run undergravel filter plates.   I spend about $10.00 a month on co2 running two 29 gallon tanks and a 20 high at around 30 ppm.

Thank you for some much needed insight. Based on your reply running the air stone with Co2 injection is added assurance that my fish won't suffer from too much Co2 while keeping Co2 levels stable. I will continue running the air stone even when the Co2 injection is going.

[Pepere]

An airstone is not ironclad protection against asphyxiating your fish.

 

you still have to be careful when dialing in the co2.  Even with several airstones it is possible to inject enough co2 to kill fish…

[BlackRubyBarber]

Thank you for pointing that out; that is true and always possible under some unforeseen circumstances. I have the lights and Co2 solenoid connected to timers and a Co2 monitor in the tank, which is helpful when I am at home. When away on vacation, of course, that is always a concern.

Edited April 27 by BlackRubyBarber

[Pepere]

Well, someone bumping against the tank can throw the needle adjuster out as well…

 

my Grandson , 4 years old, accidentally knocked the adjustment out of wack.  I was there and noticed it and corrected it.

 

I make a point of checking it after he leaves every time…

[AllFishNoBrakes]

I run sponge filters (with air stones) in the tanks I inject c02. Has worked out fine for me!

 

I should also add that I’m not going for max c02. Just an extra boost to make sure the plants don’t run out, and help outcompete algae. 

Edited April 27 by AllFishNoBrakes

[nabokovfan87]

I run a lot of air when I do run it. I almost always run it.

That being said I struggled really hard the last time to get CO2 working effectively. I run oversized HOBs and I had a skimmer and a few things going.

The main thing you want to keep in mind is spreading the CO2 around the tank. Circulation is part of the equation here. I had a lot better success removing the air stone (the filters were doing plenty of surface movement) as well as adding a pump dedicated with a spraybar to push the CO2 across the tank.

Hopefully that makes sense and helps.