Don't forget about the O2!

[ShadowMac]

:gwIn learning about planted tanks and aquascaping I heard and read a lot about the importance of CO2 fertilization, how to get it right, not too little and not too much.

In my recent experience I have discovered that the constant talk of CO2 lead me to leave out something very important for the health of any aquarium...OXYGEN!

I had struggled keeping some fish (electric blue rams) and had chalked it up to my tap water being too hard (high Kh) and my CO2 too high. Other fish I found to be fairly inactive during the day, another behavior I attributed to CO2 intolerance.

I wanted to keep my plants healthy and growing as well as stave off algae, so I kept the CO2 as high as possible without killing my fish, but algae was still a problem, growth still not optimal, and fish behavior in some species lethargic and inactive.

In an effort to save my final blue ram who had begun breathing at the surface I placed an "emergency airstone" into the tank. Within ten minutes not only had the fish's behavior improved, but also that of other fish.

I drew the conclusion that it was not CO2 intolerance, but rather a lack of oxygen.

I have since begun running an airstone 24/7. I have been able to turn my CO2 up, increase my lighting to what I had originally intended (I had reduced my lighting as low as possible to compensate for what i thought was CO2 trouble hoping that by slowing things down I could strike a balance) and everything has improved. Pearling is great, algae is nearly non existent, and my fish have never been better!

OXYGEN, OXYGEN, OXYGEN!!!!! That was the true source of my troubles.

I thought I would share this because I think many often get lost in the CO2 importance and fail to think of how O2 may play into someone's struggles with CO2

 

[barbarossa4122]

I run my air stones when co2 and lights go off.

 

[Tom Barr]

Glad you saw the light.

I was some 15 years ago when I went over to Robert's place when he lived in San Jose, and I noticed a strong tie bwt the CO2 and the O2.
I had Wet/dry filters and no such fish issues, over filtration etc.
So did some others(Steve etc).

This got me thinking.

But many do have low flow and a few fish, but the tanks could be better, I have not seen these same fish a few months later(did they die????), or fish that are very tolerant of low O2 and high CO2.

I have not seen tanks filled with discus and no flow for example and CO2.....

Generic "fish" is not a good comparative....we need the no# of fish and the type as well, if we seek to maximize the benefits for the fish, we should choose a good "canary", shrimp also fill this role well for respiration.
So just saying I have no surface flow etc, or no filter etc........and a few fish and things are fine, does not falisfy the hypothesis that they'd be less stressed if more O2 was provided.

I find it contradictory to rattle on and on over nutrients and fish, plant or shrimp health, without addressing the very basics like O2 and CO2.
Folks really avoid this and it provides far less wiggle room with dosing CO2.
Maybe not everyone, but many/most would benefit from addressing good O2 as well.

It would do not harm and only help.

 

[ShadowMac]

a couple interesting things in this process, I had trouble with acclimating and adding fish beyond a certain number. I had never considered O2 to be limiting and it seems I actually had reached a carrying capacity with O2. (although some losses could have been attributed to the four stowaways, dragonfly nymphs. But that is a different story)

My tank is a tall tank, so the ratio of surface area to volume is not optimal for great gas exchange. I had tried to improve surface agitation and had good flow (two koralias in addition to my filter) but could never quite get the effect the airstone gave me. something maybe to consider with tall tanks.

I may be gassing off a little more CO2, but the trade off is without a doubt worth it. CO2 is cheap, replacing dead fish is not.

being new, I definitely had blinders on about this issue, only focused on CO2.

I'm considering running the airstone only at night now that I have upgraded the air pump. the last one was old and intended for a smaller tank. It may be sufficient over night. I would prefer not to hear the whirring in the living room during the day.

 

[ismenio]

Why not decrease the CO2 and the light too ?

 

[ShadowMac]

i did that, and it did not fix my problem because decreasing those does not increase oxygen. it was not a CO2 issue, it was poor oxygen levels.

 

[pepetj]

I learned to keep my eyes on dissolved oxygen level due to high temperatures we get in the Caribbean basin. I have lost fish due to low DO levels in tanks without CO2. I purchased a Hach dissolved oxygen test kit that is quite hard to use and takes it time to get reliable readings,

I am running at least one airstone at night ever since in all my tanks. I have the habit of observing my fish behavior at morning time which has been helpful in preventing regrettable losses. I have turned off CO2 for a few days if I notice something wrong with my fish and let the tank without CO2 (Excel comes handy at times like this) until I have the time to monitor it for at least two hours after making adjustments in the CO2 sytem.

I just ordered a dissolved oxygen meter (waterproof Oakton DO 300 picking it up tomorrow!) since I got tired of the long and complex steps with my Hach Dissolved Oxygen test kit.

It's a balancing act to keep water surface agitation low enough to prevent CO2 degassing yet adequate levels of dissolved O2. Hopefully I will be able to "fine tune" my tanks to achieve that by measuring both variables in 5 minutes. Hach CO2 test kit is quite easy to use and I believe, correct me if I'm wrong, more reliable than drop checkers.

Is there a difference between dissolved oxygen (DO) and bio-available dissolved oxygen (DOB)? I've seen meters using those two terms.

Pepetj
Santo Domingo

 

[shoggoth43]

Depending on your filter, a spraybar across the top, or lower pointed up, should give you a similar effect without all the spray from the bubbles and may cut down on noise. This may not be an issue with your setup.

-
S

a couple interesting things in this process, I had trouble with acclimating and adding fish beyond a certain number. I had never considered O2 to be limiting and it seems I actually had reached a carrying capacity with O2. (although some losses could have been attributed to the four stowaways, dragonfly nymphs. But that is a different story)

My tank is a tall tank, so the ratio of surface area to volume is not optimal for great gas exchange. I had tried to improve surface agitation and had good flow (two koralias in addition to my filter) but could never quite get the effect the airstone gave me. something maybe to consider with tall tanks.

I may be gassing off a little more CO2, but the trade off is without a doubt worth it. CO2 is cheap, replacing dead fish is not.

being new, I definitely had blinders on about this issue, only focused on CO2.

I'm considering running the airstone only at night now that I have upgraded the air pump. the last one was old and intended for a smaller tank. It may be sufficient over night. I would prefer not to hear the whirring in the living room during the day.

 

[barbarossa4122]

Hi pepetj,

I have the habit of observing my fish behavior at morning time which has been helpful in preventing regrettable losses. I have turned off CO2 for a few days if I notice something wrong with my fish and let the tank without CO2 (Excel comes handy at times like this) until I have the time to monitor it for at least two hours after making adjustments in the CO2 sytem.

Are the plants OK when you do this ? Also, do you get any algae doing this ?

 

[barbarossa4122]

I found out that I need a higher bubble rate when the air stones are on during the co2's 8 hrs cycle. No big deal, like ShadowMac and others said....co2 is cheap.

 

[pepetj]

Hi pepetj,



Are the plants OK when you do this ? Also, do you get any algae doing this ?

Most plants are growing yet I've had some failures as well: as for algae, I have some nasty algae in two of my tanks that I'm figuring out how to control yet the majority of my planted tanks have what I call "minimum" algae, which is OK for me. Keep in mind I'm still learning EI model with liquid ferts so I may have more than one limiting factor...

Now your question got me thinking... My Osaka 155 Blue Discus Planted tank is the one with most algae problems, which grows all over Java Ferns attached to a corksheet wall where the majority of the air-bubbles are surfacing...

Pepetj
Santo Domingo