What are the root causes of Cyano?

[SauceyReef]

I am not a big believer in NP ratios, etc - since I've seen Cyano in nearly every condition - and even after many years, I can't predict where it might grow. When it comes to water chemistry, local levels may be more important than levels in the tank. I have noticed that no matter what the chemistries, cyano does not do well in tanks with high flow.

The last Cyano outbreak I had was in a high flow tank growing right where the powerhead was blasting. As I mentioned earlier though even a high flow tank can have deadspots and if they are not dealt with can lead to cyano or other algae's + nutrient increase.

Nutrient balance may not be a big factor with Cyano, but is clearly a very important aspect of tank chemistry and health. I still think it is a factor for Cyano and other algaes as well.

 

[MnFish1]

Is this a trick question? It is pretty simple. Most aquarists look for a 10:1 ratio of Nitrate and Phosphate. If you have 50-100ppm nitrates and zero traceable phosphates, or the other way around well you could probably say your nutrients are unbalanced. Balanced nutrients is one of the most discussed upon topics in the hobby AND one of the most important aspects of keeping a tank healthy...Curious what you are even talking about?? (actually not really)

Furthermore you can have a lot of flow and still have dead spots. It is about how you arrange your wavemakers, and how you clean your tank...

Dead spots in your words = "food for cyano". If all tanks have strong lights, why do all tanks not have cyano??

You think it is "lack of predators"??? Very intelligent / scientific consensus

I do not think 'most' aquarists look for a 10:1 ratio of N (though some do). IMHO - a ratio is not very helpful, since as you suggest, a 10:1 Ratio if the nitrate is 100 and P 10 is the same 10:1 as if the nitrate was 1 and the P .01. So - also as you suggest, it's not just the ratio thats important. There is a lot of anecdotal information suggesting broad success in aquaria that do not have a 10:1 N Ratio (also assuming you're not really talking about N, since we don't measure that in our tanks, as compared to Nitrate and Phosphate. The Redfield Ratio, if that is what this is based on, IMHO does not relate to our aquaria. Edit the smiley face was added by R2R. I was trying to say N to P (N)

 

[MnFish1]

The last Cyano outbreak I had was in a high flow tank growing right where the powerhead was blasting. As I mentioned earlier though even a high flow tank can have deadspots and if they are not dealt with can lead to cyano or other algae's + nutrient increase.

Nutrient balance may not be a big factor with Cyano, but is clearly a very important aspect of tank chemistry and health. I still think it is a factor for Cyano and other algaes as well.

Curious, did you have cyano everywhere else? If not, How can one postulate that chemical ratios in the water were a large influence. No offense - it would seem to for it to be very difficult for cyano mats to form in an aquarium with a powerhead was blasting it continuously

 

[MnFish1]

The last Cyano outbreak I had was in a high flow tank growing right where the powerhead was blasting. As I mentioned earlier though even a high flow tank can have deadspots and if they are not dealt with can lead to cyano or other algae's + nutrient increase.

Nutrient balance may not be a big factor with Cyano, but is clearly a very important aspect of tank chemistry and health. I still think it is a factor for Cyano and other algaes as well.

PS - I didn't mean to imply that Nitrate and Phosphate (and other levels) were not important with regards to algae. I was only saying that it seems that given the fact that cyano (and other nuisance algae) grow in many different conditions, that it seems to be difficult to pin any particular solution on ratios or absolute levels of the chemicals themselves - since there are multiple other variables that can play a role

 

[Dan_P]

Is this a trick question? It is pretty simple. Most aquarists look for a 10:1 ratio of Nitrate and Phosphate. If you have 50-100ppm nitrates and zero traceable phosphates, or the other way around well you could probably say your nutrients are unbalanced. Balanced nutrients is one of the most discussed upon topics in the hobby AND one of the most important aspects of keeping a tank healthy...Curious what you are even talking about?? (actually not really)

Furthermore you can have a lot of flow and still have dead spots. It is about how you arrange your wavemakers, and how you clean your tank...

Dead spots in your words = "food for cyano". If all tanks have strong lights, why do all tanks not have cyano??

You think it is "lack of predators"??? Very intelligent / scientific consensus

HaHa, not a trick question.

The nitratehosphate ratio as a determinant of nuisance algae growth in aquaria is much talked about. Totally agree with the term being bandied about quite often. Unfortunately, there are too many examples of cyanobacteria growing in the presence of balanced nutrients for me to be confident that such an idea has much explanatory power. If the nitratehosphate ratio was such a powerful driver of cyanobacteria growth, it could predict when cyanobacteria would grow rather than being an after the fact rationalization.

 

[Randy Holmes-Farley]

Is this a trick question? It is pretty simple. Most aquarists look for a 10:1 ratio of Nitrate and Phosphate.

Perhaps, but that isn’t a target that I recommend. IMO, both N and P should be independently targeted to desirable absolute levels. Focusing on ratios can lead to problems, such as both too low or both too high.

 

[Hans-Werner]

A ratio of the standing stock of nutrients in my eyes doesn't make much sense, for this the processing of nutrients is much too dynamic and uneven, different uptake dynamics of nutrients by different organisms etc..

What I have observed when dosing nutrients, the consumption in a reef tank with SPS and other corals seems to be around just 7 : 1 (molar ratio) for N and P. So 10 : 1 molar ratio would not be too far away. However, this has not much to do with nitrate, since nitrate is not the best option to test this nutrient consumption.

This is the reason why I am proponent of ratios in nutrient supply. It has nothing to do with standing stocks.

Corals are good in uptake of nitrogen but not quite as good in the uptake of phosphate ... or they are about equally good in uptake of both but usually the concentrations differ and they may take up different N compounds at the same time, how you want to read it.

 

[Hans-Werner]

Is it not hard to differentiate where/how the urea is broken down? i.e. I would think bacteria would do it much more quickly than coral. Bacteria, then, of course can be taken into coral - so it would be interesting to hear how you managed to separate which does what merely by adding urea to the tank?. Many bacteria contain urease.

... there are scientific articles which show urea has an effect on coral growth and the effect depends on nickel (urease!). I also can see it. So, how else does it work?

 

[MnFish1]

A ratio of the standing stock of nutrients in my eyes doesn't make much sense, for this the processing of nutrients is much too dynamic and uneven, different uptake dynamics of nutrients by different organisms etc..

What I have observed when dosing nutrients, the consumption in a reef tank with SPS and other corals seems to be around just 7 : 1 (molar ratio) for N and P. So 10 : 1 molar ratio would not be too far away. However, this has not much to do with nitrate, since nitrate is not the best option to test this nutrient consumption.

This is the reason why I am proponent of ratios in nutrient supply. It has nothing to do with standing stocks.

Corals are good in uptake of nitrogen but not quite as good in the uptake of phosphate ... or they are about equally good in uptake of both but usually the concentrations differ and they may take up different N compounds at the same time, how you want to read it.

Curious - what levels do you think are optimum (Nitrate and Phosphate) - since thats what we measure (as compared to N and P

 

[MnFish1]

... there are scientific articles which show urea has an effect on coral growth and the effect depends on nickel (urease!). I also can see it. So, how else does it work?

I agree with you that urea has an effect on coral. The question is slightly different - i.e. is there a scientific article thats been well replicated, etc, that showed that urea is 'best' for coral growth. But - to answer your question, I can see, in a lab setting, as compared to a full reef tank which is full of heterotrophic bacteria etc. that it may appear that urea is more effective (since in a lab situation, its often being dosed to a certain amount)?

 

[SauceyReef]

I do not think 'most' aquarists look for a 10:1 ratio of N (though some do). IMHO - a ratio is not very helpful, since as you suggest, a 10:1 Ratio if the nitrate is 100 and P 10 is the same 10:1 as if the nitrate was 1 and the P .01. So - also as you suggest, it's not just the ratio thats important. There is a lot of anecdotal information suggesting broad success in aquaria that do not have a 10:1 N Ratio (also assuming you're not really talking about N, since we don't measure that in our tanks, as compared to Nitrate and Phosphate. The Redfield Ratio, if that is what this is based on, IMHO does not relate to our aquaria. Edit the smiley face was added by R2R. I was trying to say N to P (N)

Well honestly most don't look at all.. But when you start going down the nutrient balance rabbit hole a large amount shoot for that ratio or close to it. It is recommended by many here, other sites/articles, and seems a solid starting point. I personally dont have near that exact ratio which shows you can have varying numbers with a nice tank. Coincidentally though when my numbers stray I deal with nuisance algae's including Cyano. Regardless to say nutrient balance is not necessary for tank health, or a factor in terms of algae or cyano growth is truly the laughable mindset. On the opposite perspective you can have what is considered a perfect nutrient ratio and still have nuisance algae like Cyano which is definitely notable.

And yes in my fluval evo I had my return pump hitting exactly where the bulk of the cyano was growing. I believe it is documented on my tank build. It still occasionally grows in that very high flow area. But keep in mind it is a nano return pump. The turkey baster I use to blow it off is clearly much more powerful.

From my anecdotal experience when my powerheads start losing power from not being cleaned and when I lapse on cleaning dead spots (even with a high flow tank) I start to see Cyano persist. It could be even with the right conditions high flow wont stop it from growing.

 

[Hans-Werner]

Curious - what levels do you think are optimum (Nitrate and Phosphate) - since thats what we measure (as compared to N and P

I agree with Randy, there is a minimum level but what is a "best level". To me, asking for nitrate makes no sense at all. Why nitrate? Most reefers who see a necessity of dosing nitrate are not talking about nitrate as a nutrient (for this the concentrations they talk about are much too high) but about nitrate as an oxidant, most likely controlling concentrations of iron in the water.

In my eyes 0.1 ppm phosphate is ok, maybe a bit more is even better. You can go quite high with controlled dosing without facing problems, at least 0.3 ppm, maybe 0.5 ppm or more.

I agree with you that urea has an effect on coral. The question is slightly different - i.e. is there a scientific article thats been well replicated, etc, that showed that urea is 'best' for coral growth.

Of course urea should have an effect on corals. I have read about Acropora corals having a "highly active urease" in a textbook about comparative animal biochemistry around 3 decades ago.

Why is it 'best' for coral growth? It is reduced nitrogen, kind of non-toxic ammonia, it has not too much organic "burden" as amino acids have, it is quite stable, and for corals it is a dual use compound. Also, uptake, processing and effect on coral growth are scientifically proven. To me this sounds quite good.