Help me understand the relationship of oxygen, co2, ph and nuisance algae.

[LRT]

Help me get my head wrapped around this please.
I understand higher oxygen levels helps raise ph.

Do higher oxygen levels help fuel growth of nuisance algae and other bacteria?

Do higher levels of co2 help fuel growth of nuisance algae and other bacteria?

Proper level of oxygen to aim for and maintain in reef tank? I'm assuming once I hit reccomended ph of 8.2 ish?

I feel like since ive raised my oxygen levels I'm seeing nuisance algae seriously begin to subside.
This may also be due to that fact I have really upped my fresh air exchange as well as sumps bubbling and turning over much faster and im assuming thats helping get the co2 out of water?

Am I thinking this right?

TIA

 

[flampton]

Well actually O2 doesn't directly affect pH levels at all. Increasing the turnover of your tank will allow CO2 to equilibrate with the room CO2 % which will usually raise the pH of the tank. (not always true if living in a small space with lots of breathers, haha) Turnover also allows the tank O2 to equilibrate with the room O2 % so you could use pH as a 'sign' that aeration is proper.

Hypothetically speaking increased O2 'may' improve growth of bacteria/algae in certain regions of your tank but it would really be hard to quantify in any meaningful way. It would also discourage the growth of more O2 sensitive organisms within certain regions of the tank.

Higher CO2 would potentially increase growth of problematic organisms

O2 levels don't correlate with pH so I would never definitely say pH 8.2 has enough oxygen. I'm not sure what the O2 of my tank is but I know that because of my atmospheric conditions up here in Flagstaff (air here is only 16% O2 v. 21% at sea level) I know that O2 is a potential problem, especially in power outage situations, but I have no problem running pH 8.2. Again that is because it is the CO2. In fact I've been considering one of those sochting oxydators to increase my O2 but haven't looked into it enough.

If the above is unclear I'm sure some of the others tagged could chime in.

 

[Garf]

Extreme levels of CO2 certainly fuel algal growth. I messed with that 7 or 8 years ago on a waterfall scrubber. I can also confirm that CO2 pooling on a sumps/tanks surface can lower pH.

 

[LRT]

Extreme levels of CO2 certainly fuel algal growth. I messed with that 7 or 8 years ago on a waterfall scrubber. I can also confirm that CO2 pooling on a sumps/tanks surface can lower pH.

Can you elaborate a little more on the scrubber part? I recently put a diy ats in hopes of pulling excess co2 out of water while algae grew on the waterfall.
Is this correct in thinking that this is what I will achieve?

 

[LRT]

Well actually O2 doesn't directly affect pH levels at all. Increasing the turnover of your tank will allow CO2 to equilibrate with the room CO2 % which will usually raise the pH of the tank. (not always true if living in a small space with lots of breathers, haha) Turnover also allows the tank O2 to equilibrate with the room O2 % so you could use pH as a 'sign' that aeration is proper.

Hypothetically speaking increased O2 'may' improve growth of bacteria/algae in certain regions of your tank but it would really be hard to quantify in any meaningful way. It would also discourage the growth of more O2 sensitive organisms within certain regions of the tank.

Higher CO2 would potentially increase growth of problematic organisms

O2 levels don't correlate with pH so I would never definitely say pH 8.2 has enough oxygen. I'm not sure what the O2 of my tank is but I know that because of my atmospheric conditions up here in Flagstaff (air here is only 16% O2 v. 21% at sea level) I know that O2 is a potential problem, especially in power outage situations, but I have no problem running pH 8.2. Again that is because it is the CO2. In fact I've been considering one of those sochting oxydators to increase my O2 but haven't looked into it enough.

If the above is unclear I'm sure some of the others tagged could chime in.

Huge problem for me in Mesa as well. Ive never tested my co2 but can tell you last summer was horrible having to keep windows closed for 4 months in 100+ weather.
I'm hoping to fix that by adding and inline pump that pulls fresh air from outside with airstones in my sumps. As well as intake and exhaust and seal fish room as good as I can.

Since ive added the stones and got my sumps rolling with windows open my water has almost totally cleared up. Not sure if I've ever seen it this sparkling clean.
Most defientely has helped getting proper aeration at least.
Summer is coming though and don't want to be counterproductive and pound all that co2 back in.

 

[Garf]

Can you elaborate a little more on the scrubber part? I recently put a diy ats in hopes of pulling excess co2 out of water while algae grew on the waterfall.
Is this correct in thinking that this is what I will achieve?

Yes, algae will uptake CO2 as you describe and increase pH. It can also convert bicarbonate into CO2 which requires extra effort, so probably not preferential. In my unscientific meddling I added CO2 to a scrubber and doubled its mass to about 800grms for a standard canvas. This also caused bacterial growth downstream without a noticeable increase in nutrient removal. I seduced I had messed with the algae’s C:N: P ratio.

 

[LRT]

Yes, algae will uptake CO2 as you describe and increase pH. It can also convert bicarbonate into CO2 which requires extra effort, so probably not preferential. In my unscientific meddling I added CO2 to a scrubber and doubled its mass to about 800grms for a standard canvas. This also caused bacterial growth downstream without a noticeable increase in nutrient removal. I seduced I had messed with the algae’s C:N ratio.

Interesting. I just recently experienced a huge cyano outbreak in my sumps.
I thought that I caused that by deep cleaning my sumps with shop vac.
I wonder if setting up ats had anything to do with the cyano explosion.

 

[Garf]

Interesting. I just recently experienced a huge cyano outbreak in my sumps.
I thought that I caused that by deep cleaning my sumps with shop vac.
I wonder if setting up ats had anything to do with the cyano explosion.

When I first looked into scrubbers on Santa Monica’s site I posted the possibility that algal exudates could possibly fuel cyan, Dino outbreaks etc. No, was the reply. Never believed him, although I haven’t experienced such problems.

 

[LRT]

When I first looked into scrubbers on Santa Monica’s site I posted the possibility that algal exudates could possibly fuel cyan, Dino outbreaks etc. No, was the reply. Never believed him, although I haven’t experienced such problems.

Probably didn't help that I run a 100% barebottom system. Probably threw chemistry all out of whack when I shop vacuum the sumps. Its what I assumed anyway.

 

[Garf]

Probably didn't help that I run a 100% barebottom system. Probably threw chemistry all out of whack when I shop vacuum the sumps. Its what I assumed anyway.

I’ve got a bare bottom now. Feed the crap out of it just to have detectable N and P.

 

[taricha]

Do higher oxygen levels help fuel growth of nuisance algae and other bacteria?

Do higher levels of co2 help fuel growth of nuisance algae and other bacteria?

Proper level of oxygen to aim for and maintain in reef tank? I'm assuming once I hit reccomended ph of 8.2 ish?

Extreme levels of CO2 certainly fuel algal growth. I messed with that 7 or 8 years ago on a waterfall scrubber.

Nuisance algae or not nuisance: Photosynthesis is a strong driver of producing O2, but a well aerated tank is probably near max anyway, so it isn't like blasting light helps push O2 higher (in an aerated system).

More surprising to me is the potential of photosynthesis to drop the CO2 concentration and increase pH. I saw some pH data from @Dan_P recently on what happens when an algae film growing in a bucket is driven with light. pH's higher than I thought possible in saltwater (low to mid 9s) . Numbers that mean CO2 was drained almost totally - again, not something I thought possible. After adding a bubbler, still crazy high pH.
(lesson for me: aeration is slow to equalize CO2, and photosynthesis is fast at dropping CO2 - in some cases even an aerated tank can't keep up with photosynthesis in dropping CO2) Algae scrubber folks being fanatical about flow and bubbles and turbulence are not wrong.

Let's get weirder:
At night, the photosynthesis of algae stops, but the metabolism continues. A blob of algae in the dark can consume a good bit of oxygen and maybe even become anoxic (locally).
I once put a 1 or 2 cm^2 hunk of cyano from my glass into sealed 12mL tube of tank water overnight and found that it lowered the O2 in the tube by ~3mg/L (out of ~6.5 or 7) compared to a second tube of just water.

All photosynthetic stuff needs CO2. More would encourage it, but it's not like you could zero out CO2 to deprive algae.

 

[LRT]

Nuisance algae or not nuisance: Photosynthesis is a strong driver of producing O2, but a well aerated tank is probably near max anyway, so it isn't like blasting light helps push O2 higher (in an aerated system).

More surprising to me is the potential of photosynthesis to drop the CO2 concentration and increase pH. I saw some pH data from @Dan_P recently on what happens when an algae film growing in a bucket is driven with light. pH's higher than I thought possible in saltwater (low to mid 9s) . Numbers that mean CO2 was drained almost totally - again, not something I thought possible. After adding a bubbler, still crazy high pH.
(lesson for me: aeration is slow to equalize CO2, and photosynthesis is fast at dropping CO2 - in some cases even an aerated tank can't keep up with photosynthesis in dropping CO2) Algae scrubber folks being fanatical about flow and bubbles and turbulence are not wrong.

Let's get weirder:
At night, the photosynthesis of algae stops, but the metabolism continues. A blob of algae in the dark can consume a good bit of oxygen and maybe even become anoxic (locally).
I once put a 1 or 2 cm^2 hunk of cyano from my glass into sealed 12mL tube of tank water overnight and found that it lowered the O2 in the tube by ~3mg/L (out of ~6.5 or 7) compared to a second tube of just water.

All photosynthetic stuff needs CO2. More would encourage it, but it's not like you could zero out CO2 to deprive algae.

Awesome thank you for this! For the first time in my reefing life I finally feel like maybe a light bulb is coming on.

Funny you mention cyano. Its what has me thinking about all this. Like I said earlier I recently shop vac my sumps and had a huge cyano explosion all over my rock. Some 18-25 yrs old directly from ocean last year.
Just a thick matt across both sumps 100% covered and started chunking off and floating in water.
Anyhow I hit my system with chemiclean and literally watched the cyano begin dissolving. Honestly the more air I pushed at it the faster it went away! Almost 100% free of cyano 48hrs later.
Point is it didn't happen until super heavy aeration occurred. That got me wondering is it the chemiclean thats killing it or the super heavy aeration or both?
What is chemiclean and why does it need and work so well with aeration?

Have you ever taken a chunk of cyano and put it in something and super aerated it? If so did it kill it? Or what do you think would happen?

Thank you for feedback. I'm going to get some macro algae to help out compete the nuisance algae for sure. I know for sure my co2 levels must have been astronomical. Wifes cooks everyday. Huge dog. 3 adults. Constant company and a sealed house 6-10 months a year.
Going to try macro along with algae scrubber. Keep system aerated and see how that pans out.

 

[Dan_P]

Help me get my head wrapped around this please.
I understand higher oxygen levels helps raise ph.

Do higher oxygen levels help fuel growth of nuisance algae and other bacteria?

Do higher levels of co2 help fuel growth of nuisance algae and other bacteria?

Proper level of oxygen to aim for and maintain in reef tank? I'm assuming once I hit reccomended ph of 8.2 ish?

I feel like since ive raised my oxygen levels I'm seeing nuisance algae seriously begin to subside.
This may also be due to that fact I have really upped my fresh air exchange as well as sumps bubbling and turning over much faster and im assuming thats helping get the co2 out of water?

Am I thinking this right?

TIA

You received great responses so far. I just wanted to add that when dealing with algae or nuisance microorganisms, you are likely dealing with a complicated network of interactions between many microorganisms, making it difficult to establish a cause and effect relationship. For example, a sudden appearance of cyanobacteria isn’t necessarily a sudden change in only one species. Behind the scenes, there might have been an explosion in a bacteria population that made rapid cyanobacteria growth possible. The surfaces of our aquaria are extremely complicated biofilms that are not necessarily stable ecologies and are not easily manipulated.

 

[taricha]

Anyhow I hit my system with chemiclean and literally watched the cyano begin dissolving. Honestly the more air I pushed at it the faster it went away! Almost 100% free of cyano 48hrs later.
Point is it didn't happen until super heavy aeration occurred. That got me wondering is it the chemiclean thats killing it or the super heavy aeration or both?
What is chemiclean and why does it need and work so well with aeration?

Have you ever taken a chunk of cyano and put it in something and super aerated it? If so did it kill it? Or what do you think would happen?

I do not know why chemi-clean needs so much oxygen, (and if it's the actually mechanism of the drug action on algae - I'd love someone to explain it to me).

The likelier explanation is that chemiclean caused cyano death as expected, but it took a further few days for it to break apart and dissipate.

Super-aerating cyano just ensures that the water has max O2 and CO2 near equal to room CO2. I wouldn't expect cyano would be harmed by that. Certainly not disappear over a day or two.