oxygen and co2

[QldRobbo]

Hi,
Just a quick question...

When hooking up co2 injection, I was told to remove the air bubbler. Does the oxygen the fish require now come from the plants processing the co2 into oxygen?

I had co2 hooked up for past few days but didn't have any plants until today, and my fish have started gasping today, so I've put the bubbler back on for now.

BTW, my co2 is only around 7-8ppm at the moment, so its not that I'm injecting too much.

Cheers

[Cory Keeper]

Generally speaking, yes, O2 comes from the plants. What the air bubbler does is create surface agitation. This agitation creates gas exchange, and alot of CO2 is then lost/wasted.

[tanker]

If you are putting in CO2 you would not need the "air-bubbler". These thing do not "PUT" air into water. Water gets O2 from the water surface. The "bubbler" causes water movement so there is more "surface" so you loss CO2 in the water, which in turn increases O2.

[beviking]

Hi,
Just a quick question...

When hooking up co2 injection, I was told to remove the air bubbler. Does the oxygen the fish require now come from the plants processing the co2 into oxygen?



Yes, the oxygen comes from the plants. BUT, you have to have enough plants...enough HEALTHY plants. That isn't to say you need to cram every empty bit of space with plants...just don't expect two stems to be enough for an "overstocked" aquarium. Which leads to the next question...if at only 7-8ppm of CO2 your fish were gasping, it seems that there may be a lot of fish for that tank. Incidentally, CO2 and O2 are independant of each other. There is a maximum each can attain in any given environment but it is possible to have max O2 and max CO2 at the same time. It sounds to me that your tank was lacking oxygen, not that it had too much CO2 (if that wasn't too obvious :) ). Apparently your filter is not disturbing the surface either?

[QldRobbo]

It sounds to me that your tank was lacking oxygen, not that it had too much CO2... Apparently your filter is not disturbing the surface either?


I realised this, why I stated that it is only 7-8ppm co2 and therefore not too much co2... I knew that it was a lack of oxygen which is why I needed to know where the fish are meant to get that oxygen from.

I also know that air gets into the water from the surface, and the bubbler is just agitating the water which is counter productive to injecting co2, but I am more concerned about my fish.

I may turn off the co2 today (to not waste it) leave the bubbler on and make sure that the fish all look fine later today, and if so then turn off the bubbler and put the co2 back on and make sure the fish continue to look ok... now that I have a few plants

Thanks for your help

[Notophthalmus]

Plants only use CO2 when exposed to light. You can have your bubbler on at night to improve oxygenation, and your CO2 on in the day to help your plants.