CO2/O2/Surface agitation

PeterGwee

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Jan 23, 2005
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Hi Tom, I was wondering if you can still get O2 saturation from a tank with quite a lot of surface agitation even with good CO2? You mention that aeration after the night drives off excess O2...does that mean that excessive surface agitation during the photoperiod even though with good CO2 will prevent a planted tank from reaching O2 saturation above 100%?

Regards
Peter Gwee
 

Ian H

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Jan 24, 2005
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Shipley, West Yorkshire, UK
Re: CO2/O2/Surface agitation

Sorry to leap in here Peter but I was about to ask a question related to yours.

I've read somewhere that surface agitation oxydises fertilizers and shouldn't be done. I run a small powerhead during lights out because I leave the CO2 running 24/7. Without this my fish are gasping in the morning.

I'm getting decent results in my tank with this regime and to my mind increasing the O2 levels to 100 plus percent would oxydise things anyway. Or am I missing some point here?

Ian
 

Tom Barr

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Jan 23, 2005
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Re: CO2/O2/Surface agitation

PeterGwee said:
Hi Tom, I was wondering if you can still get O2 saturation from a tank with quite a lot of surface agitation even with good CO2? You mention that aeration after the night drives off excess O2...does that mean that excessive surface agitation during the photoperiod even though with good CO2 will prevent a planted tank from reaching O2 saturation above 100%?

Regards
Peter Gwee


Yes,but as with many things.....
People think more is better........

No so, a moderate amount, some movement, not a torrent is good and desirable in all cases.

Excess surface agitation (ESA) during the photoperoid will remove O2 as much as it will after the lights go out. It will add O2 when the lights are about to come on for 2-8 hours at night in most tanks, again, depends on plant production/light and nutrient levels.

Excess O2 does not cause any oxidizing issues, they can talk theory all day, but the practical issues with that and UV use at the scales we use it is insignificant.

I'm not about to worrying about well growing plants in order to prevent some nutrients from being oxidized.

Growing plants, not conserving nutrient ionic state is the goal here.
I never quite understood why folks make a big deal over that.

Seems many times folks lose sight and micro manage way too much.
Look at the big picture.

They also add ETDA, Gluconate, DTPA and other chelators for Cu, Fe, Zn, Mn........

High O2 levels will drive the heck out of nitrifying bacteria=> less NH4 and more rapidly mineralization of all organic waste into inorganic plant available forms.

High O2 levels in and of themselves have not been shown to reduce algae growth much, but there is some effect, we all have seen it and thriving tank.

I think it's bacterial related, but not a direct relationship.

So in an indirect way, higher plant production = more O2= more O2 for bacteria(and fish/inverts) to process this faster greowth rate and waste production= less algae.

I orginally thought: High O2= poor algal growth.
Isolated, this does not seem to be the case.

But when you add the other elements, it seems to be the case and is something you could test.

Regards,
Tom Barr
 

Cornhusker

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Jan 23, 2005
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Re: CO2/O2/Surface agitation

tom, i have allways used small hobby pumps in my tanks that run 24/7, about half way down into tank, for extra circulation. is this wrong? thanks,cornhusker