Undetectable Nutrients but still have hair algae

[Hans-Werner]

I do not claim to know the truth but I hardly ever had 8° KH or above, usually 5.5 to 7.5, and calcium at 450 ppm or a bit higher but I nearly never had problems with green hair algae except when adding things like amino acids. Precipitating phosphates out of the water also seemed to be a good method to get hair algae. So to me it looks like a bad or unbalanced N-P-ratio in the water and phosphates in the rock can cause hair algae. Also hard corals don´t like the unbalanced N-P-ratio since they have no access to the phosphates stored in gravel and rock.
Coralline algae in my experience need some nutrients more than they need an alkalinity above 8° KH. I am sorry if I am missing the truth, it is just my experience.

 

[Julian Sprung]

Reporting one's experience, ESPECIALLY when it flies in the face of conventional wisdom, is a good practice, as it brings everyone closer to understanding the truth. I think that there really is a piece or pieces of the puzzle to be discovered in the observations you've made, but it is a leap to take measurements, note the events in the aquarium, and then connect their cause to an idea like N-P ratio. I agree that phosphate in the substrate is accessible to Derbesia sp. GHA algae, but it is a stretch to claim that lowering phosphate in the water promotes the GHA only because they are thus stimulated to access that source. They will grow on inert, phosphate-free substrates too when conditions are right. Corals not liking unbalance N-P ratios? That would need some controlled experiments. I haven't seen good evidence of that. Most reef aquariums run at unbalanced N-P ratios. If you see unhappy corals plus GHA it can be the combined effect of low alkalinity (which corals tolerate, but don't love) plus the stimulation of GHA (which produce organic leachates that corals don't like). What actually stimulates GHA? In my opinion the main factors are low alkalinity, low pH, source of phosphate, source of iron. If GHA persist after adjustments are made to raise alkalinity (in a balanced way), and low pH is not an issue, and phosphate levels are low, and there is not an unusually large source of iron, then the use of herbivores should solve the problem. I have not seen a strong correlation to nitrate level. Like you I have made inferences based on measurements and observations, so I am open-minded to the possibility that there are more pieces in this puzzle to be discovered.

 

[Hans-Werner]

What is low alkalinity, please? The natural normalized (to 35 psu salinity) alkalinity is 6.5° KH (6.4 to 6.7° KH in the Pacific with 6.5° KH or lower in the Tropics) in the oceans nearly all over the world. In my experience SPS tolerate elevated alkalinity but they don´t like it either. I have published an article that showed that high alkalinities over 9° KH may produce tissue necrosis in Acropora sp. in a short time more than twenty years ago and found it always confirmed since then (I ran low phosphate concentrations most of the time). In experiments I found that SPS even don´t like alkalinities as low as 8° KH (with balanced supply of calcium and alkalinity) when the phosphate concentration is low.
I also have done some experiments with nutrient additions and all other parameters seemed to be constant. I have started my first experiments with phosphate and nitrogen compounds about twenty years ago. I think I know a bit about what corals like. I am less sure with GHA because I had them only a few times.

 

[PSXerholic]

Like Julian's statements ;-)
It is for non scientific people hard to understand what this really is about and how the N-P ratio actually truly works ;-)

With truly no nutrients, if that is the case, you starve your tank, Corals won't color and will look real ugly in a while if not already, and you will never get the Algae issue under control.
Raise Nutrients and keep them in the Redfield ratio ;-)
For "normal" folks,
following the Redfield ratio or Buddy ratio just ensures your nutrients are balanced in a way that potential nuisance algae have a less desirable environment to thrive, hence less chance of algae issues.
This is based on the Liebig's law of minimum which you can apply to almost every form of life.......

I always had great success to keep my tank algae issue free, when applied this ratio for nutrients.
Todays problem is with low nutrient systems or worse, non detectable nutrients in many tanks, the fine tuning in these low ranges is not as easy to maintain without automatism, and even harder with smaller tank systems due to instability in small systems.

If this is maintained, and Algae issues won't get resolved within 4-6 weeks after correction, you need to start looking for other potential issues such as waste, excessive iron or other algae fueling elements.
But in most cases, just the balanced nutrients and sufficient patience for a few weeks will resolve the situation.

Here a graph covering the lower ranges a bit better.

Reference - Picture as Courtesy out of Andre's Reef Guide for Coral Colorization Part#1


Quick recent Video of a balanced tank with happy Corals ;-)


-Andre

 

[PSXerholic]

Like Julian's statements ;-)
It is for non scientific people hard to understand what this really is about and how the N-P ratio actually truly works ;-)

With truly no nutrients, if that is the case, you starve your tank, Corals won't color and will look real ugly in a while if not already, and you will never get the Algae issue under control.
Raise Nutrients and keep them in the Redfield ratio ;-)
For "normal" folks,
following the Redfield ratio or Buddy ratio just ensures your nutrients are balanced in a way that potential nuisance algae have a less desirable environment to thrive, hence less chance of algae issues.
This is based on the Liebig's law of minimum which you can apply to almost every form of life.......

I always had great success to keep my tank algae issue free, when applied this ratio for nutrients.
Todays problem is with low nutrient systems or worse, non detectable nutrients in many tanks, the fine tuning in these low ranges is not as easy to maintain without automatism, and even harder with smaller tank systems due to instability in small systems.

If this is maintained, and Algae issues won't get resolved within 4-6 weeks after correction, you need to start looking for other potential issues such as waste, excessive iron or other algae fueling elements.
But in most cases, just the balanced nutrients and sufficient patience for a few weeks will resolve the situation.

Here a graph covering the lower ranges a bit better.

Reference - Picture as Courtesy out of Andre's Reef Guide for Coral Colorization Part#1


Quick recent Video of a balanced tank with happy Corals ;-)


-Andre

In addition, the tank should maintain decent healthy ALK, CA, MG as well "need" to be in a healthy PH range to avoid these Algae issues.........................

Yes, this hobby is complex on the chemistry side................

 

[Centerline]

This whole thread is about why GHA (Derbesia) grows despite low phosphate. So much speculation beating around the bush and totally missing the truth. "... low phosphate causes hair algae in most reef tanks"? That's a complex theory that I believe is nonsense. Many years ago I wrote a book, Algae: A Problem Solver Guide. In it I gave the answer to the question posed by this thread. It's simple. GHA is a symptom of low alkalinity. The photo of Tristan's tank on page 3 of this thread screams LOW ALKALINITY. Practically no coralline algae anywhere. GHA taking over. Phosphate does play a role in GHA growth, but removing it is not the only solution... you have to boost and maintain alkalinity. Try dosing kalkwasser daily, and add C-Balance to maintain an alkalinity at or slightly above 8 dKH with a calcium level at or slightly above 400. The GHA will die back and the corallines will take over. Nitrate is hardly relevant. There are additional influences that sometimes are involved in these GHA blooms, such as a excess source of iron and persistent low pH (closed air space, elevated CO2), but in most cases the problem is simply a matter of the maintenance of calcium and alkalinity balance and keeping alkalinity up.

So this is interesting! I have a tank that is very clean and runs fairly high alk - Alk-11/Mag-1450/Cal-450 - weekly water changes, a little carbon dosing and if I'm not carful ZERO P as tested on a Hanna ULR. Constant pain in the butt as I have to dose both P&N. You would not expect to see any hair algae in the tank but in fact there is. Reading your post and seeing the persistent low PH comment I have to wonder as that has been a problem for me and I finally added a C02 scrubber a month ago. Not much has changed in the last month but maybe that will do it!

 

[PSXerholic]

So this is interesting! I have a tank that is very clean and runs fairly high alk - Alk-11/Mag-1450/Cal-450 - weekly water changes, a little carbon dosing and if I'm not carful ZERO P as tested on a Hanna ULR. Constant pain in the butt as I have to dose both P&N. You would not expect to see any hair algae in the tank but in fact there is. Reading your post and seeing the persistent low PH comment I have to wonder as that has been a problem for me and I finally added a C02 scrubber a month ago. Not much has changed in the last month but maybe that will do it!

But I hope your PH has increased at least!

Also you need some Nutrients !!!!
If you have issues to keep them detectable, you need to rethink about your methods of nutrient reduction.
Sounds to me, you do too much or too effective ;-)

-Andre

 

[Centerline]

But I hope your PH has increased at least!

Also you need some Nutrients !!!!
If you have issues to keep them detectable, you need to rethink about your methods of nutrient reduction.
Sounds to me, you do too much or too effective ;-)

-Andre

Ph has gone up a little. Low of 7.8 from 7.5 and high of 8.3. So thats coming along. Nutrient trouble when I mixed prodibo and N0P0x. Really didn't need one or the other. However, that was 4 months ago and its been a pain. ORP dropped to 170 or so within the week and you can guess the rest. And yes, nutrients are up because I feed and dose, endlessly

 

[Hans-Werner]

The theme has changed a bit now. Low pH is normal with that high calcium and alkalinity and that low nutrient concentrations. The cause is that every kind of calcium carbonate precipitation releases CO2 and depresses pH in that way. When calcium carbonate precipitates on the heater, pumps or also when corals or calcareous algae (coralline and Halimeda) calcify always there is CO2 released. Corals and algae assimilate the CO2 to form sugars and other carbohydrates. But when water is such oversaturated they don´t need to take up much CO2 to calcify or viewed vice versa a little calcification releases enough CO2 for assimilation. So photosynthesis does not elevate pH as much as it would with more phosphate in the water and less calcium carbonate oversaturation. I recommend less calcium and alkalinity supply and lower calcium concentration and alkalinity. I guess you will see that also the corals will like it. Maybe a bit more phosphate would be fine too.

 

[Hans-Werner]

Just another idea about the low pH that is frequently noticed with that constellation: There is a relative oversupply of inorganic and organic carbon in relation to phosphorus and nitrogen compounds. Corals and coralline algae are limited by phosphorus and nitrogen and cannot take up as much CO2 as they could if they had a better supply of phosphorus and nitrogen. The pH stays low. GHA are less limited by phosphorus because they have access to the phosphates in rocks and start to grow. Here we come back to the role of competition between corals, coralline algae and GHA. If GHA rely on free CO2 as carbon source they could have an advantage due to the low pH and even high alkalinity.

 

[tmtmtm]

If you're using D-D H2Ocean Pro salt, that might be one of the reasons. Personal experience.

 

[PSXerholic]

The theme has changed a bit now. Low pH is normal with that high calcium and alkalinity and that low nutrient concentrations. The cause is that every kind of calcium carbonate precipitation releases CO2 and depresses pH in that way. When calcium carbonate precipitates on the heater, pumps or also when corals or calcareous algae (coralline and Halimeda) calcify always there is CO2 released. Corals and algae assimilate the CO2 to form sugars and other carbohydrates. But when water is such oversaturated they don´t need to take up much CO2 to calcify or viewed vice versa a little calcification releases enough CO2 for assimilation. So photosynthesis does not elevate pH as much as it would with more phosphate in the water and less calcium carbonate oversaturation. I recommend less calcium and alkalinity supply and lower calcium concentration and alkalinity. I guess you will see that also the corals will like it. Maybe a bit more phosphate would be fine too.

@Hans-Werner , so basically you're saying that a low nutrient tank, would look much cleaner from the water quality in lower CA and lower ALK levels, than with higher CA and ALK parameter?

-Andre