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Discussion Starter · #1 ·
This may seem obvious, but is there a correlation between algae growth and O2 difficiency? I have some BBA and string algae, and it seems to grow in the same areas of my tank. I got thinking that it may have to do with the fact the O2 levels in those areas are low and thus the bad algae.

Has anyone considered O2 dosing the same as we do for CO2? I am going to try and airpump with a diffusing stone on a timer at night to up the O2 concentration and see how it works to "boost" the system. My plants are doing fine but not bubbling as I like, so the O2 must be supplied to help.

I admit my Eheim 2217 filter, for a 125 gallon tank is perhaps a little underpowered for the tank, and I am considering getting a 2213 (small canister) to supplement the current.

To think some think cultivating beautiful plants would easy or so addictive.
 

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I did a test of various algae species using High O2, high CO2 and ambient CO2and ambient O2.

I did a mix of

CO2/O2 high
Low O2/high CO2
High O2/low CO2
Ambient low O2/CO2

There were no differences in algae growth for all the tanks.
High CO2= 25 ppm
High O2 = 15ppm(higher than most anyone's O2 levels in their tanks

I speculated high O2 as being the reason for retardation of algae growtrh when plants grew well(see old APD post, dating back 8 or more years now).

Note: more filtration, current etc, is not the same as adding pure O2 gas.
It will help keep the O2 somewhat stable and higher if you do not have good plant growth though......

Regards,
Tom Barr
 

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So does that mean the common myth of BBA=Co2 defficiency busted? Does CO2 just boost the growth of plants and does not retard BBA?
yes and no. from what i understand is that you boost CO2 so plants can do their photosynthesis thing better and take up the nutrients algae would take up otherwise.


oh, and I just read on wiki that O2 does interfere with cyano's (BGA) process because of their structure... But it sound like O2 has no effect on real algae. BGA are bacteria.
 

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Discussion Starter · #8 ·
Thanks Tom. You just saved me a lot of work. So is the better solution to simply add another filter (albeit much smaller) to supplement the current in my tank? I am assuming if the algae is in the same areas that current must be to blame, as once the nutrients are gone or lacking they cannot be replenished in time by osmosis alone. Funny, my wife had a small Cichlid tank a few years ago with a 2213, and I gave it away to a friend not thinking I would need it again. At least it was a friend.
 

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So does that mean the common myth of BBA=Co2 defficiency busted? Does CO2 just boost the growth of plants and does not retard BBA?
No, not one bit.
No plants where added.

High O2 = less algae growth, that was the main hypothesis that was shown to be false.

I had the same amount of algae(as measured in total Chl a levels per unit area), but different species in some treatments.
In the higher O2 levels: GSA and diatoms predominated much more.

High CO2 that's stable, or low CO2 that's stable etc will stop new BBA growth.
It generally will not kill existing growth, after the BBA grows older, the adults die off generally, about 3-8 weeks.
So adding lots of CO2, then having it bob all over will not solve the issue.

Adding another filter is not a bad idea.
It'll help mix the CO2 better and you should always focus on that if the BBA is appearing.

It's not just about adding more CO2.
It's about providing good distribution, good flow through the reactor/by the diuffuser, so that the for the tank's size and shape, there is an even amount of CO2 available to the plants.

It's not about outcompeting the algae etc, it's about providing them with a good stable nutrient/CO2/light tank.

Non CO2 tanks for example have low CO2, lower light, lower nutrients and stable conditions, we see the same observations with BBA: none.
But as the non CO2 plant tank shows, they balance of the nutrients/light and CO2 all match well and are stable enoyugh to provide good growth, just about 10X slower than with cO2.

Regards,
Tom Barr
 

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Discussion Starter · #10 ·
So Tom:

I can provide all the nutrients with abundance. Would simply a powerhead suffice to simply move the nutrients about. Of course, we would not get one too powerful, but enough to ensure the tank was well circulated?
 
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