# Algae are nutrient scavengers



## Dolly Sprint 16v (8 Nov 2009)

Gang@ukaps

After reading a considerable amount of non UKaps threads - the above subject is readily talked about. One question that cannot be answered is.
Q. The algae that is present within the water column scavenages on:

A. The surplus fertz left by the plants that have not been consumed during the lighting periodicity

B. The fertz that are within the water column waiting to be comsumed by the plants - thus when it is lighting time there is a limited amount of fertz for the plants which produces poor growth / unhealthy plants.

I even read in one thread where a guy had green spot algae deposits on the Co2 diffuser - actual on the ceramic plate  , DC's where lime green / off yellow in their colouration, very minimal surface water movement to retain Co2 during non lit tank time - nobody new of a suitable answer for this issue.

Any thoughts 
Regards
Paul.


----------



## George Farmer (8 Nov 2009)

Flyfisherman said:
			
		

> I even read in one thread where a guy had green spot algae deposits on the Co2 diffuser - actual on the ceramic plate


Lack of water circulation around the actual ceramic plate, pehaps.  Typically they're recessed in a glass housing.  I've experienced the same.  They're usually white too, that attracts more algae.


----------



## ceg4048 (8 Nov 2009)

First of all algae don't scavenge. If there is any scavenging to be done it's done by the plants. Plants are the ones that need the most nutrition so their work is a lot harder. Algae don't care about nutrient levels. They can succeed whether there are high levels or low levels of nutrients in the water column. So the idea that algae are hanging around waiting for plants to finish feasting just so that they can fight over the last remaining crumbs of nutrients is absurd. I mean, what's the implication? That the nutrient level must be exactly zero by the time lights are off in order for the algae to starve to death? How does one propose to accomplish that? Good luck.

Non-growing surfaces are easy targets for algae. Plants that are growing are able to resist attachment. Inorganic surfaces will always have some algae on them because they don't grow. Light is the single most important factor in algal growth so a white inanimate object sitting under bright lights will typically attract algae. That's just how life is so we need to get over that fact. I have external diffusers and if I wrap them in cloth to block the light they don't get algae and I never have to clean them. If they are open to the light they get algae. This is completely independent of nutrient levels. 

What's more important is keeping the plants - and tank in general healthy as a system, and that's accomplished by having well fed plants, good CO2 and good circulation - and to stop obsessing about whether we have excess nutrients or not. It's a pity people don't obsess over whether they have excess light. Then there might actually be some progress. 

Cheers,


----------



## George Farmer (8 Nov 2009)

ceg4048 said:
			
		

> It's a pity people don't obsess over whether they have excess light. Then there might actually be some progress.


Salient point!


----------



## aaronnorth (8 Nov 2009)

> Algae don't care about nutrient levels



agreed, someone linked a paper to me arguing you can starve algae by limiting N&P, they didnt read it and/ or understand it but the levels recorded were in micromilligrams and algae growth persisted.


----------



## Mark Evans (8 Nov 2009)

ceg4048 said:
			
		

> It's a pity people don't obsess over whether they have excess light. Then there might actually be some progress.



i've cottoned on to this a few months back. for me light is more important than co2.


----------



## CeeJay (8 Nov 2009)

Hi


			
				saintly said:
			
		

> i've cottoned on to this a few months back. for me light is more important than co2.



Me too. :idea: 
Lighting, or control of it, turned out to be my biggest friend when I recently came back from holiday to a tank full of algae  
I'd left someone to carry out my EI dosing while I was away. Bad move. Whilst they dosed correctly, they were not paying attention to what was going on in the tank.
Unfortunately, I lost one of my Rummy nose tetras which the tank caretaker didn't notice. Obviously this decomposed, or was eaten, or both, but he carried on dosing and the algae had a field day. Took me 3 weeks to get the tank back on track.
All sorted now, but what a learning curve   . 
Now back up to a tank full of 'lemonade' at lights out, after gradually increasing my lighting back up to previous levels  . (oh, and many, many water changes   ). 

Chris


----------



## plantbrain (9 Nov 2009)

Well, my issue has long been getting at that light<=>CO2 balancing/time factor.
This is still more a plant growth issue.

For algae, it's a germination issue, what causes them to be dormant vs bloom?

Plants do not go dormant, nor have his same life history in our aquariums, they are merely a function of growth/death. These two groups cannot be compared on equal terms.

Regards, 
Tom Barr


----------



## Dave Spencer (13 Nov 2009)

I struggle to understand what people mean by "excess nutrients". Are we talking about nutrients that are above the needs of the plants during lights on? If so, how does dosing a planted tank work? Clive suggests that people are alluding to all the nutrients being depleted by plants at the end of the photoperiod. If so, then there is an excess of nutrients for the other 99.9% of the time the lights are on. How on earth do we ensure all the nutrients are used up together?

I just don`t get it. 

Dave.


----------



## dw1305 (13 Nov 2009)

Hi all,
I'll "nail my colours to the mast" straight away, and say that I have an academic background in Botany and Horticulture, and I've worked as an Ecologist (mainly looking at nutrient cycling in terrestrial grasslands) for almost 20 years.  From that background I'm happy to accept that nearly all plants (and in this I'll include all photosynthetic organisms) will show elevated growth with the addition of CO2 and macronutrients (as long as micronutrient levels and PAR are not limiting). 
If anyone isn't sure of the effect of additional carbon, I recommend this experiment using Cabomba <http://www-saps.plantsci.cam.ac.uk/articles/cabomba/cabomba.htm>.

However I am to some extent wary of adding both CO2, and to some extent macro-nutrients, to the water column in  aquaria. The reason for this is the differences between "sustainable" and "optimal" growth. As a general rule In natural communities the most biodiverse and stable communities are those that occur in nutrient limited conditions, this is partially because nutrient limited plants are physically smaller and you can get more individuals on the same area. I also know that patchy environments have a higher "edge effect", and support more biodiversity. 

My suggestion for a planted tank that will never suffer from "outbreaks" of algae (or rapid unbalanced plant growth), is one with reasonable amounts of PAR, but *extremely limited nutrients in the water column*, and a lot of structure (wood, peat blocks, bark, stones etc.), with a "biofilm" present. This removes the balancing act between nutrients, CO2 and light. Nutrients are always severely limiting. Growth will never be optimal, but it will be sustainable.

You may not be able to grow all the plants that are available, but you can still grow a good range, and there is very little that can go wrong. In fact the only parameter that I measure regularly is conductivity, and I aim to keep this under 100 microS. Very occasionally I do add a small ball of clay with grains of "growmore" to the root zone of Echinodorus, and I initially added a small amount of  both leaf-mould and calcined clay to the silica sand substrate in the area in which I planted the Cryptocorynes, but the tank in the photo has been running for over 4 years and still has acceptable plant growth.

<


>

Therefore, with the following proviso's:
if you are happy to have some "biofilm", 
some build up of mulm (and DOC)
grow plants which  can grow in low CO2/low nutrient conditions,
make regular small water changes, (with good quality water low in nutrients)
don't over stock with fish
accept Asellus, MTS, Shrimps, Planaria etc in the tank.

You can have a tank with good plant cover and little algae that is very stable and resilient.

cheers Darrel


----------



## ceg4048 (13 Nov 2009)

Hi,
   Sorry, but I don't buy this theory and I don't really believe this to be true:


			
				dw1305 said:
			
		

> However I am to some extent wary of adding both CO2, and to some extent macro-nutrients, to the water column in  aquaria. The reason for this is the differences between "sustainable" and "optimal" growth. As a general rule In natural communities the most biodiverse and stable communities are those that occur in nutrient limited conditions, this is partially because nutrient limited plants are physically smaller and you can get more individuals on the same area. I also know that patchy environments have a higher "edge effect", and support more biodiversity.


I see no correlation between biodiversity and organism size. You can pick any terrestrial or aquatic system on the plant and by a large margin, the most productive systems are those that are high in nutrients. Of course, those nutrient levels may not be found in expected places such as in sediment. The Amazon Rain Forest is big, with both big and small creatures, and is the very definition of biodiversity, yet the sediment is very poor in nutrients. The nutrients are stored in the forest litter itself so the plants there have developed special adaptation and symbiotic relationships to pull nutrients out of the litter.

Highly productive aquatic systems such as those found in the Pacific reefs, such as Hawaii or The Marianas Islands normally have their nutrient stores thousands of feet below the summit which feeds the planktonic life forms, upon which is the basis of oceanic production. You cannot have high productivity without high nutrient loads, and the productivity of a system determines the level of it's biodiversity.



			
				dw1305 said:
			
		

> ...However I am to some extent wary of adding both CO2, and to some extent macro-nutrients, to the water column in aquaria. The reason for this is the differences between "sustainable" and "optimal" growth.


Yes, but what does this even mean? Fish tanks are not independent entities living on their own. Therefore "sustainability" is a relevant expression only as it relates to the extent to which the owner of the tank is willing to sustain it. "Optimal" is another expression that has no meaning within the context of a man made system. What parameter(s) are you using as a metric for optimal? Growth rate? If so then it's clear that more nutrients+CO2 generates higher growth rates and better plant health. Is the expression "optimal" being used to describe some sort of balance, or ratio, such as the ratio of maintenance required versus growth rate? If so then each person must decide how much maintenance they are willing to do, how much money they are willing to spend and how much growth performance they expect in order to determine what is optimal for them



			
				dw1305 said:
			
		

> My suggestion for a planted tank that will never suffer from "outbreaks" of algae (or rapid unbalanced plant growth), is one with reasonable amounts of PAR, but *extremely limited nutrients in the water column*, and a lot of structure (wood, peat blocks, bark, stones etc.), with a "biofilm" present. This removes the balancing act between nutrients, CO2 and light. Nutrients are always severely limiting. Growth will never be optimal, but it will be sustainable.


OK, that's fine, but that's only one of many possible scenarios. Severely limiting nutrients, which only produces severely limited growth is not my idea of an interesting tank. I have huge PAR levels, huge CO2 levels and enormous nutrient levels and I don't have algal outbreaks. Of course this requires a lot of attention, but I'm willing to pay it. If I were not, then I would have to lower the PAR as well as nutrients+CO2. Far more often than not, people have high PAR and insufficient nutrients+CO2 and that does cause algal outbreaks. The OP claims that nutrient levels in the water column is the causal factor and what we are saying is that the causal factor is high PAR. Certainly, the algae will feed on the available nutrients so this can exacerbate the issue by accelerating the algal growth, but the presence of nutrients alone does not cause the algal outbreaks. This is the key point.



			
				dw1305 said:
			
		

> You may not be able to grow all the plants that are available, but you can still grow a good range, and there is very little that can go wrong. In fact the only parameter that I measure regularly is conductivity, and I aim to keep this under 100 microS. Very occasionally I do add a small ball of clay with grains of "growmore" to the root zone of Echinodorus, and I initially added a small amount of  both leaf-mould and calcined clay to the silica sand substrate in the area in which I planted the Cryptocorynes, but the tank in the photo has been running for over 4 years and still has acceptable plant growth.


Well, I mean, suppose I _want_ to grow all the plants that are available? Then what? Am I simply outta luck? That's not a very scientific solution. A much more viable solution is to learn and understand the role of nutrients and CO2 as they relate to plant health. I don't ever worry about conductivity and it's often above 750 microS. That whole clay ball thing is completely unneccessary. My Echinodorus grow just fine with water column dosing which results in a hypereutrophic environment.

The thing is that if you are satisfied to have the plants in your tank merely eek out a living then that's fine, lower the light and do the "sustainability" thing. That is certainly a valid. But I want my tank to sing, and I want it to amaze me. And that is very difficult to achieve under limiting conditions. The plants below were dosed with over 60ppm NO3, 10ppm PO4 weekly, had high CO2 and were under 1/2 kilowatt of T5  with reflectors. I guarantee you that you cannot achieve this by starving the plants. And look Ma, no algae.

























Cheers,


----------



## CeeJay (13 Nov 2009)

Hi

How did I just know something like that was coming   


			
				ceg4048 said:
			
		

> The plants below were dosed with over 60ppm NO3, 10ppm PO4 weekly, had high CO2 and were under 1/2 kilowatt of T5 with reflectors.


   

Just have to say though Clive, stunning plants.

Chris


----------



## paul.in.kendal (13 Nov 2009)

*+1 - on all counts!*


----------



## dw1305 (13 Nov 2009)

Hi all,
I thought that would probably be the response, and I'm not looking to pick an argument. It is very much "horses for courses", and I don't think we will ever agree. However just to answer some of Clive's comments, which I do think are to some degree valid. 


> I see no correlation between biodiversity and organism size. You can pick any terrestrial or aquatic system on the plant and by a large margin, the most productive systems are those that are high in nutrients. Of course, those nutrient levels may not be found in expected places such as in sediment. The Amazon Rain Forest is big, with both big and small creatures, and is the very definition of biodiversity, yet the sediment is very poor in nutrients. The nutrients are stored in the forest litter itself so the plants there have developed special adaptation and symbiotic relationships to pull nutrients out of the litter.


Productivity is "biomass", I am talking about biodiversity, I agree with The Amazon comments, as you say the whole system is both nutrient poor and biodiversity rich, because the *few nutrient present are continually being re-cycled, and the input of solar energy is huge*. 


> Highly productive aquatic systems such as those found in the Pacific reefs, such as Hawaii or The Marianas Islands normally have their nutrient stores thousands of feet below the summit which feeds the planktonic life forms, upon which is the basis of oceanic production. You cannot have high productivity without high nutrient loads, and the productivity of a system determines the level of it's biodiversity.


This is back to the rainforest, in this case even within a zone of upwelling this is relatively nutrient poor water, if you want to see nutrient rich sea water stand on the Seven Bridge above the Bristol Channel gyre in the spring, that is nutrient, (and sediment) rich water, and 





> "the productivity of a system determines the level of it's biodiversity"


 is, no two ways about it, wrong, if you felled an area of rainforest and planted a C4 grass - Sugar Cane for example, productivity will be greatly increased, although you now have a single plant "monoculture", and exactly the same amount of PAR.  The highest theoretical productivity would be a simple plant mixture with a canopy that fully exploited the incident PAR.


> OK, that's fine, but that's only one of many possible scenarios. Severely limiting nutrients, which only produces severely limited growth is not my idea of an interesting tank. I have huge PAR levels, huge CO2 levels and enormous nutrient levels and I don't have algal outbreaks. Of course this requires a lot of attention, but I'm willing to pay it.


And you can see the result, no-one is going to argue that my tanks are anything like as beautiful, or diverse as yours, but they are much more stable, and I am willing to bet that for many of us less skilled aquatic gardeners my approach offers a more achievable, and sustainable objective.  


> Well, I mean, suppose I want to grow all the plants that are available? Then what? Am I simply outta luck? That's not a very scientific solution. A much more viable solution is to learn and understand the role of nutrients and CO2 as they relate to plant health. I don't ever worry about conductivity and it's often above 750 microS. That whole clay ball thing is completely unneccessary. My Echinodorus grow just fine with water column dosing which results in a hypereutrophic environment. The thing is that if you are satisfied to have the plants in your tank merely eek out a living then that's fine, lower the light and do the "sustainability" thing. That is certainly a valid. But I want my tank to sing, and I want it to amaze me. And that is very difficult to achieve under limiting conditions. The plants below were dosed with over 60ppm NO3, 10ppm PO4 weekly, had high CO2 and were under 1/2 kilowatt of T5 with reflectors. I guarantee you that you cannot achieve this by starving the plants. And look Ma, no algae.


Yes, that is my point I am happy to have a limited range of plants in my tank merely eek out a living, but this is not because I don't fully understand the role of nutrients and CO2 as they relate to plant growth, it is because I want stability above all, not an all singing, all dancing tank.

cheers Darrel


----------



## ceg4048 (13 Nov 2009)

dw1305 said:
			
		

> ...Yes, that is my point I am happy to have a limited range of plants in my tank merely eek out a living, but this is not because I don't fully understand the role of nutrients and CO2 as they relate to plant growth, it is because I want stability above all, not an all singing, all dancing tank.


 Hi Darrel,
   Yes, and I think that's great. As I mentioned earlier, if that's your focus then that's just as valid a course of action as any. The issue here however, as stated by the OP was that high nutrient levels attract algae. My point is that we all have choices and we need not limit our choice to the methodology of poor nutrient levels only. I am at one end of the spectrum and you are at the other. But by seeing the differences each person can choose for himself/herself just how much singing and dancing they want to do and are not limited to your end of the spectrum alone. I think that's the heart of the issue and this is what I'm trying to illustrate. 

Also, you seem to be attributing the stability of your tank to low nutrient levels and I believe that to be a miscorrelation. Whatever stability you have is strictly due to your lower PAR, not the lower nutrients, because there is a much higher probability of instability if you raised the PAR and kept the nutrient levels the save versus raising the nutrient levels and keeping the PAR the same. Low PAR lowers the nutrient uptake demand. If you were to add more nutrients right now what would be the results? I think I can predict that if you currently have say, small amounts of CO2 related algae  then they would feed on the nutrients and you'd see an increase in their density. If you had small amounts of nutrient related algae you'd see an increase initially and then they would recede, followed by higher growth rates. Many people suffer the first case, such as thread or BBA. Then, if they are told to add more nutrients without their advisor identifying the algae they see an increase. They then erroneously concluded that nutrients unilaterally cause algae. The school of thought that considers nutrients a menace also worships other myths which conspire to prolong the agony.

High energy tanks do require that you stay on top of things. That's just how life is. I don't think that many people are attracted to the hobby by looking at plants that are barely eking out a living. Attraction, fantasy, imagination and desire will be stoked by the amazing. Isn't that why we have aquascaping in the first place? Why should stability be a more valued asset than beauty? So the easiest path to amazement and beauty clearly is appropriate application of CO2/nutrients. Is there a possibility of screwing things up? Of course, but so what? We're here to help you figure out the mistakes. I know exactly where the path to nutrient limiting leads. I've been down that road, and I know it's not where I want to be. Again, that's just a personal view. Choose a path, stability or amazement, but isn't it better to see  where each path can lead in order to choose the right one?

Nutrients and CO2 are still quite poorly understood generally, so it's very easy for folks to be swayed by scare mongering. My purpose is to counter those arguments aimed against nutrients/CO2 and to show, first and foremost, that these components in and of themselves are not a causal factor in the problems that plague so many tanks. To focus away from nutrient paranoia and to think more carefully about the real causal factors such as lighting, filtration/flow, maintenance and so forth. The nutrient paranoia crowd are always at a loss to explain why our eutrophic tanks do not suffer algal blooms.

Now, you claim that your approach of limiting nutrients offers a more achievable objective. I say go to the Algae section of this forum and see how many gardeners suffer chronic poor health and algal outbreaks as a direct result of inappropriately limiting nutrient/CO2. Then count the number of those who solve their problems by then adding nutrients/CO2. Then, go to the Lighting section and count the number of threads that start off assuming one needs megawattage to grow plants. Again, I'm sure I sound like an insufferable extremist but I try to push the very boundaries of what is achievable with nutrients/CO2. What I learn along the way I'm happy to share.

Most simply don't understand the relationships between light/CO2/nutrients, or even the very basics of plant growth. But it can be explained, and I prefer to explain and to show the truth than to simply issue the same old dogmatic principles. I don't suggest that an unskilled gardener go over the top as I do, but what I am demonstrating is that you can go over the top because the "evil nutrients" as we have been led to believe is actually an ally, and that if I can get such results at the extreme end then dosing at more "reasonable" levels will likewise generate success. Nutrient paranoia is a disease of this hobby, a plague that hinders both artistic and botanical development. Knowledge and truth are the cure.


Cheers,


----------



## dw1305 (16 Nov 2009)

Hi all,
With thanks to Clive for the time he has spent on this post. Although I don't post very often, I've lurked on this forum for quite a while and I find much of the discussion here very interesting, and as the pictures earlier in this thread illustrate, what is possible truly amazing.  

I think that as aquarium keepers we are always juggling light and nutrients, I'll include CO2 in this, (as well as as O2, nitrate etc.), but by adding CO2 and macro-nutrients (I'll assume for this that all micro-nutrient levels are in the range required for healthy plant growth) you are juggling a lot more balls, are lot higher, and unless you are a very skilled juggler, who fully understands the trajectories of all the balls, the potential for something to go wrong is much increased. 

This is why I think the suggestion that for most algae ridden situations adding nutrients and CO2 will always help is dangerous, if things are out of balance, for me it  is always better to return to a known datum (low nutrients, atmospheric CO2) rather than adding both nutrients and CO2 on the grounds that soon or later things will stabilise to a new datum. For example in the lab., I've got a state of the art nitrate probe, it is a thing of beauty but realistically it is of little practical value in telling me what the nitrate status of my tank water is. Additionally if I want to know how metal rich my water is I need to run a filtered sample through the Atomic Absorption Spectrophotometer, use colourimetry for orthophosphates and if I want to get an approximate value for how eutrophic a water sample is I need to run a 5 day BOD (although a conductivity meter will give me a quick approximation). 

I am at a practical disadvantage compared to many of the members of this forum, in that I have never kept a high tech. aquarium., although I have worked with hydroponic tomato growing (including using propane burners to increase CO2 levels), and the phytoremediation of waste waters using Reeds, Willows, Water Hyacinth etc.  However I don't think  





> Whatever stability you have is strictly due to your lower PAR, not the lower nutrients, because there is a much higher probability of instability if you raised the PAR and kept the nutrient levels the save versus raising the nutrient levels and keeping the PAR the same. Low PAR lowers the nutrient uptake demand.


 is right. I can't measure PAR (I don't have a "photon flux density meter") and whilst I have about 2w per(US)g, on most tanks, some of the tanks are under the glasshouse high pressure sodium grow-lamps  (supplying about 15,000 lux at bench level) and are getting at least 20 watts per m2 for 12 hours a day (measured last night), even assuming that they receive no additional daylight (they actually receive daylight as well), the plant growth is slightly tighter for some of the floating plants (Pistia particularly), but otherwise things are fairly similar. This is because nutrient are still limiting, the analogy I would have would be with an Amazonian clear water river flowing from very old, very hard rocks, it has some vegetation growing but that is severely nutrient and CO2 limited (just atmospheric), but PAR is truly immense, somewhere in between 200 - 300w per m2. (PAR figures from <http://en.wikipedia.org/wiki/Insolation>.)

cheers Darrel


----------



## ceg4048 (16 Nov 2009)

Hi Darrel,
            Thanks for your input as well mate. As you noted, we're always happy to discuss these issues because we feel that they are fundamental to the success and enjoyment of the planted tank. Without a doubt there are pitfalls, and the road is even rockier when we increase the spectral energy levels. Honestly, you don't really need to be able to measure PAR to understand it's effects or to realize when your PAR is high or low, hence the generalized WPG rules of thumb. Of course, these rules are becoming outdated as we see developments in lighting technologies, T5, HQI, LED. We know from those hobbyists who do have PAR meters, that anything below about 2WPG of a typical T5 installation generates PAR values somewhere in the neighborhood of 100 micromoles or so at the surface with falloff at depth more or less commensurate with the inverse square law. Experience has shown therefore that generally, if you keep below this threshold, you can run a non-CO2 enriched tank using T. Barr's non-CO2 method with very much reduced nutrient loading and elimination of water changes.

To be fair, I should point out that there are brilliant examples of what can be achieved with non-enriched, such shown by Dusko in this thread Diana Walstead style tanks Dusko is very skilled at low tech tanks and he focuses on keeping the lighting levels low to solve many problems such as in the thread; Green Water - Dusko's lazy solution to the problem but certainly there is no need to run away from nutrients even in a non-enriched environment. There are very good reasons for the non-enriched approach, such as the low maintenance, low speed factors. As stated previously, if these issues are important then low tech should be considered.

If someone has never tried the high tech approach then it's very easy for them to assume that it's fraught with danger and that as you imply, that it's a frightful juggling act. The only reason this happens is when folks attempt it without understanding the principles if light/CO2/nutrients. The dosing principles are very simple as described in the dosing Tutorial EI DOSING USING DRY SALTS

All too often, would-be high tech hobbyists run out and spend lots of dough on high lighting and neglect to consider the more important aspects such as CO2, flow and nutrients. Then they get algae and the first thing they want to do is to complain about high nitrates/phosphates. I see this every day, so I'm familiar with all the nutrient hating arguments. That's why I'm adamant that the root of all evil in planted tanks is high PAR. Whether you can measure it or not, it's fairly easy to know when some has too much PAR. 

When we advise the algae ridden hobbyist that the first thing to do is to lower the light they are appalled, because they had just spent all this money on fancy luminaries. So the misery continues until they can somehow improve the flow/distribution, CO2 and nutrient levels to match their PAR. I never had algae in my enriched tanks until I got high lighting, and I didn't solve my algae problems until I optimized CO2/nutrients/flow. Then it was necessary to understand the causes of algae, if in fact they were not caused by high nutrient loading, and that was a lot more difficult, because there are so many optical illusions. Some insights are discussed in Why dont nutrients cause algae?

Cheers,


----------



## plantbrain (17 Nov 2009)

Darrel, 

I think coming at this from an ecologist perspective plays a large role into your view.
It's understandable also.  

Still, this is not the same goal, management etc as a natural system. 
Many natural systems have high CO2 in them. They also have high nutrients etc as well. And clear pretty water you'd love swim in, spend a day floating around in.

They are stable, over long time frames. The main variable is light.

We can easily see algae are not limited by CO2 nor nutrients relative to vascular plants.
Light is about 10-30X more intense in natural systems and rather tough to control :idea: 
So is CO2, so what is left? Nutrients. That's the only growth factor left,m typically N or P.

So what about in aquariums?
Well, we can control CO2, nutrients and importantly, light.

Light is where all growth starts, it drives CO2 uptake/demand and that drives nutrient uptake a demand.
In water, this is a very different scenario than terrestrial systems for CO2 and O2 exchange.

By adding enriched CO2 and nutrients, we allow the plant to allocate everything to light gathering.
Algae are more light limited under this situation.

Fast growth of plants reduces the colonization rate on leaves, so there's less issue of that over time, combined with algae herbivores, and lower light.

I'm not sure if that helps, I know you feel a bit overwhelmed anf may feel some of this is baloney, but if you go to the basics of plant growth, allocation of resources at the whole plant level, it makes a lot of sense.

The blame for most issues is high light, which leads to CO2 demand/supply issues, and then the NO3/PO4 gets balmed somehow at the end of the day by many hobbyists  I think from a test/research model, the aquarium with plants is a fun model to work with.

Read up on Tropica's web site also. Ole's and Troel's articles are good for the hobbyists/Claus has been around since before me also and is a very sharp feller.

I think you follow growth logically, the light will make more sense. Light => CO2=> nutrients.
There is a nice diagram on CO2 and light on Tropica article web site that illustrates the growth/allocation principles for high/low light and high low CO2.

We could also add a 3rd component: nutrients, but the diagram starts to get harder to understand with more complexity.
But it behaves similarly to the light/CO2 if you reduce it enough, it can limit growth and thus limit the CO2 demand and the ability to use light efficiently.

Hope that helps.
I rarely tell anyone to use CO2 unless I first know what *their/your goal is, that is where all advice should start.*
Never what we want, that is not our right/nor their question  
There are trade offs for various management methods. No one method will be all things to all people, so you need a number of management methods in your tool box to be a good manager/adviser for this hobby.

Non CO2 slow growth, low input(the more/most organic sustainable method). Very easy, but low growth rates, limited species selection.

I advocate this a lot but many point their green thumb at my name with EI dosing.
Or marine macro algae aquariums and reefs.

Blah, you cannot win  

I think also, good aggressive debate helps folks learn on both sides. 
Some think this is a personal argument, it's not. Have a laugh, learn, debate and enjoy. I live around more tomatoes than you EVER want to see. The trucks spill them all over the roads here every summer/fall. Vegan road kill I call it.

Regards,
Tom Barr


----------



## plantbrain (17 Nov 2009)

Here's some nice examples of natural systems with high CO2 and nutrients(loads of fish in them also):

Florida where I take folks each year to see:









Marine:




This weed is considered rare and difficult by many outside the USA:


----------



## plantbrain (17 Nov 2009)

Another rare(ha!) plant by many folk's standards:








Search 
Bonita Springs, Mato Grosso,
Ichetucknee Springs Florida
Rainbow river Florida
Pupu springs NZ etc

All have high CO2, loads of fish, good stable nutrients(never limiting), moderate to high light depending.
Ichetucknee Springs comes right out of an old PO4 mine and the state park was bought from the mining company about 30 years ago.

Nitrogen from septic systems, cattle, certain species of algae, exotic aquatic weeds threaten these systems. Pesticides, endocrine disruptors from humans can destroy these wonderful places that are very useful for recreation and park lands.

 Must see places.

Regards, 
Tom Barr


----------



## dw1305 (17 Nov 2009)

Hi all,
Thank again for the posts, I think they have added to this thread. Tom they are lovely photos, we have a lot of trout fishing "chalk streams" the Wylye, Salisbury Avon, Kennet etc locally, they are still clear, although abstraction and eutrophication has taken it's toll on the fishing. What is the plant with the accumulation of "marl" on its roots? it is not one I recognise.  Seeing the marl reminds of the Burren in western Ireland, with its turloughs and marl lakes, here's Lough Bunny <http://static.panoramio.com/photos/original/11429692.jpg>, very clear, but not quite as warm.

I must admit I deliberately tried to leave high pH, highly buffered, carbonate saturated water (these are?) out of the equation, due to the extra level of variables thrown up by both the carbon dioxide >< carbonate >< bicarbonate equation and the conversion of orthophosphates to relatively insoluble calcium phosphate compounds, as well as the variable CEC  of the sediments etc.

I agree that there is no argument that  plant growth is enhanced by higher macro-nutrient, and particularly nitrogen levels. In fact for many plants its a linear growth response up to very high levels of nitrogen, I even co-authored a paper on the nitrogen response of plants for schools, using hydroponic radishes <http://www-saps.plantsci.cam.ac.uk/journals/ward.pdf>. The same with carbon, we do the "Cabomba" experiment ( http://www-saps.plantsci.cam.ac.uk/articles/cabomba/cabomba.htm earlier in the thread, using 1% sodium hydrogen carbonate solution as the carbon source), in classes and the increased oxygen evolution is quite startling.  

I have seen "Dusko's Walstad tank" article, very impressive, I also like the EI thread and "James' Planted Tank - All In One Solution" <http://www.theplantedtank.co.uk/allinone.htm> and "Dosing with Ammonia and Urea" etc. They may not be what interests your standard aquarist, but they certainly interest me.

It probably is my ecological background, but If I was purely growing aquatic plants in an aquaria with the aim of growing the "best" plants, (and I'd agree that many of the plants illustrated couldn't be any better condition than they are), I would have no qualms about growing them with plenty of light, an added carbon source, ammonium nitrate as a nitrogen source etc., but personally I wouldn't do it in a planted aquaria with fish and/or inverts, and I couldn't advise any-one else to do it either.

I've probably said all that I can usefully say now, so I'll go back to "lurking", but I'm sure I will carry on  enjoying the vast majority of posts.

cheers Darrel


----------



## plantbrain (17 Nov 2009)

dw1305 said:
			
		

> Hi all,
> Thank again for the posts, I think they have added to this thread. Tom they are lovely photos, we have a lot of trout fishing "chalk streams" the Wylye, Salisbury Avon, Kennet etc locally, they are still clear, although abstraction and eutrophication has taken it's toll on the fishing. What is the plant with the accumulation of "marl" on its roots? it is not one I recognise.  Seeing the marl reminds of the Burren in western Ireland, with its turloughs and marl lakes, here's Lough Bunny <http://static.panoramio.com/photos/original/11429692.jpg>, very clear, but not quite as warm.



Marl= calcium and magnesium carbonates, they are declaifying the water to get DIC(or Carbon/CO2/ using HCO3 as a source). Common in hardwater plants.



> I must admit I deliberately tried to leave high pH, highly buffered, carbonate saturated water (these are?) out of the equation, due to the extra level of variables thrown up by both the carbon dioxide >< carbonate >< bicarbonate equation and the conversion of orthophosphates to relatively insoluble calcium phosphate compounds, as well as the variable CEC  of the sediments etc.



Then the plant is really CO2 limited, and must use Bicarb as a DIC source.
Vals, Egeria, Hydrilla etc are good at this, most of the 400 species we keep do not.
All plants prefer the gas CO2. Sometimes PO4 can be caught in the Ca/CO3 mix.



> I agree that there is no argument that  plant growth is enhanced by higher macro-nutrient, and particularly nitrogen levels. In fact for many plants its a linear growth response up to very high levels of nitrogen, I even co-authored a paper on the nitrogen response of plants for schools, using hydroponic radishes <http://www-saps.plantsci.cam.ac.uk/journals/ward.pdf>. The same with carbon, we do the "Cabomba" experiment ( http://www-saps.plantsci.cam.ac.uk/articles/cabomba/cabomba.htm earlier in the thread, using 1% sodium hydrogen carbonate solution as the carbon source), in classes and the increased oxygen evolution is quite startling.



You might use DIY CO2 from yeast and repeat the Cabomba test
You can measure the CO2 production at different temps of the yeast brew to show how yeast enzymes respond to temp changes. Then you can also test the plant response to elevated CO2[aq] and then compare that to HCO3 sources of DIC.

Now you have a pretty cool class room test of 3 things and can break the students up into groups to focus on each.
Or do them in stages and have them collect CO2 via inverted test tube in water to measure gas volume between treatments(say pH and temp over a range to get a bell shaped curve). Then the CO2 brew can be used along with Bicarb sources of DIC and you can measure the O2 production ins a sealed chamber over time with a rubber gasket for an O2 probe or take samples of the water and reseal.

Plenty of nice options for enzyme kinetics, even color spectrum use, DIC sources, allocation, temp effects, pH effects rates etc etc. Light intensity is also a good one and O2 production, electron transport chain can be measured even using a color metric blue solution and say spinach pulp/chloroplast. The blue color will be increases as more NADPH is available to reduce the blue indicator(clear= no reduction, blue= reduced).   

A good paper on nutrients for aquatic plants is Gerloff's 1966 paper.
Old but good. EI dosing is about 1/5th of that Hoalgnad' modified version there. Which is about what the one of the authors suggested(Paul K) some years after. So the targets are very similar.

The weeds they chose are bicarb users though, not obligate CO2 gas users, say like all moss and liverworts species. 
You could also compare the effects of one or two species of each type for CO2/Bicarb use and then measure the O2 production.



> It probably is my ecological background, but If I was purely growing aquatic plants in an aquaria with the aim of growing the "best" plants, (and I'd agree that many of the plants illustrated couldn't be any better condition than they are), I would have no qualms about growing them with plenty of light, an added carbon source, ammonium nitrate as a nitrogen source etc., but personally I wouldn't do it in a planted aquaria with fish and/or inverts, and I couldn't advise any-one else to do it either.



Dose makes the poison.
Respiration is also a 2 way street, both O2 and CO2 needs addressed, not just one, or the assumption that "less is best". It's more a question of management and is there really any significant risk if the NO3 is say at 30ppm vs 1ppm?

If not, then there's no need to such management and maintaining low NO3 in an aquarium.
How to test that? Use a canary. Crystal red shrimp, hyper sensitive invert due to heavy inbreeding, easy to bred so plenty of culls available to test. Same approach can be used with plant species also, pick a sensitive one to test with or a collection of the wimply touchy species.

If there is no significant difference between say 5 ppm NO3 and say 30ppm, then why bother obsessing and going to more labor if there is no benefit? Environmental management does not operate on hearsay and myth. They test and check to see if there is some risk based on some model and hopefully improve over time and get better and better, not test will be perfect or answer any ultimate truth, only get a bit closer.

Complete elimination is not practical, nor required.
This(elimination) is an often used argument and hyperbole used in the Environmental field and the aquarium hobby on both sides.



> I've probably said all that I can usefully say now, so I'll go back to "lurking", but I'm sure I will carry on  enjoying the vast majority of posts.
> 
> cheers Darrel



I think the general notion you have is well placed and caring, so explore it, see what you think, what the evidence, what test you can cook up and try out and see. Do they make sense? Can you falsify a hypothesis you make? How might you make a reference to compare to? Demonstrate, prove it to yourself, your own eyes. Then you have learned something, challenged your own and gone down the path.

Classrooms and aquariums are very useful tools for teaching such concepts.
Then you see the range/results.

So post to your heart away  

Regards, 
Tom Barr


----------



## plantbrain (17 Nov 2009)

BTW, since you teach, I think the phytometer is an excellent tool and something even middle school kids can do at some level, to college grad level. Wetland plants can be used and grown in various sediments, salinities (marine salt or ethylene glycol etc for water potential), emergently so there's no interaction with CO2 demand/limitations/foliar nutrients.

Those intenractions can/could be added later, subsequently  if you wanted to.

You can measure the N and P in the tissue, various organs, LAI, %OM, root shoot ratios etc etc and do analysis there.

BTW, no single management method shall be all things to all people, there's also a human factor in there that is huge.
So learn several method to have several management tools available to help various management goals.

I do.

Hopefully more will try different approaches and then fairly compare the trade offs.
Many are trying the non CO2 methods out after first doing the higher light/CO2 enrichment methods.

This aquarium has not seen a water change in 2 years:






No CO2, fish waste recycle, they do add a small amount of ferts, but demand is also small, export is via plant trimming, very low input, high efficiency, the sustainable index is more than any other type of aquarium BTW.

No water changes, low labor input, no testing, refill water, trim once every 2-3 month, feed fish.
Even plain fish only systems need more work than that.

I have a non CO2 Zebra pleco tank:




I'll add some floating emergent plants to the wood, much like a snag in a river with emergent plants stuck:





Another good paper is Madsen and Cedergreen 2002:
http://www.ingentaconnect.com/content/b ... 2/art00011

_Callitriche_ cannot use Bicarb as a DIC source.

Good paper.

Looks at water column and Ole also did some work in Danish streams to this same effect.

Sediment and the water column both are good sources.
I use them both for management, not just one/or the other.
Both must be considered when looking at any system where aquatic plants/algae are growing.
Some folks do not, hobbyists have few methods to measure sediment sources, only the water column, so it's hard to blame them for fingering the water column to blame.

Here's a neat paper also about algae, nutrients, and macrophytes in a more applied aquarium (tropical to subtropical, similar plants species, temps, depths etc)

http://fishweb.ifas.ufl.edu/Faculty%20P ... ophyte.pdf

Not much correlation with algae, plants, submersed or otherwise and nutrient state of the lakes.
Very low R squared values across the board.

Seems like high N or P is a poor model to use for planted aquarium and algae, and trophic status.
The paper is certainly more applied to hobbyists plant species, temps, depths, algae + plants together, than any others I've run across. High number of lakes with plants in there. So good comparative results also.

They did not look at CO2, although Crisman is wondering about that the last 2-3 years.
Give the papers a good read and see what you think.




Regards, 
Tom Barr


----------



## dw1305 (18 Nov 2009)

Hi all,
Tom thanks for the references and phytometer picture, we are a bit limited with what we can do with our postgraduate trainee science teachers (by the "National Curriculum"), but we do regularly do one other photosynthesis experiment, using the wonderfully entitled "algal balls", details here <http://www-saps.plantsci.cam.ac.uk/articles/broad_light.htm>.

I'm hoping to get the Aquaria set back up in the Lab., so I'm looking for teaching project possibilities arising from these, so far I've got agreement to set up a "Winogradsky column" http://www.biology.ed.ac.uk/research/groups/jdeacon/microbes/winograd.htm, but I haven't got any further. 

cheers Darrel


----------



## CeeBee (26 Nov 2009)

George Farmer said:
			
		

> ceg4048 said:
> 
> 
> 
> ...



I can attest to this being the truth.  I recently decided to increase the lighting period of my second lighting beam and am now wishing I hadn't due to a resurgence of BBA and what I think might be brown algae (not really getting why I've got the brown algae though).  I only increased the time on the second beam by 1 hour.

It was all going so well but I had to go and tweak it


----------

