# Nutrient levels and algal growth



## Vaevictus (Mar 24, 2010)

Hi all,

I am trying to get my head around the EI method of dosing ferts.

I have algae (I think it is hair algae) all over my back wall of my tank, one of those polystyrene moulded tree bark style things, and I have it growing in my java moss and it has already started to dust the leaves of my new plants.

This is a 450 litre well cycled tank.

So I want my plants to grow and not the algae right? 

I am dosing EI but I just cant help but feel that I am also feeding the algae.

Algae will grow even when the plants will not so I understand the thinking in ensuring that the plants are not limited by anything, but I cannot understand how this will ultimately get rid of the algae.

If algae is thriving while limited, surely it will thrive even more if it is not limited?

How can the plants out-compete the algae if all nutrients are in ample supply?

Thanks for helping me understand this.......


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## mistergreen (Dec 9, 2006)

First, algae is taking over because you've created conditions for it to thrive like high light, low nutrients + CO2, some NH4, and or little plant mass.

And second, once algae have taken hold, yes they'll stay for good unless you remove them or kill them with excel, H2O2 etc...

You'll have to fix your parameters & remove the algae to give your plants a chance.


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## StaleyDaBear (Apr 15, 2010)

in agreeance with what mistergreen said. Steps = 1. fix underlying problem (what is REALLY limitng plant growth/nutrient uptake? Lack of co2? lack of nutrients? Lack of plants?) 2. Manually remove 3. Create environment where there will be no limiting factors so the higher lifeforms can outcompete for nutrients. This means sometimes pumping your co2 to unsafe levels and bringing it back down gradually, dosing the #@&* out of your tank to keep nutrient's up, and maybe even raising your light so the demand on both your co2 and nutrients are less intense.


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## Nate McFin (Mar 19, 2009)

Here is an interesing place to start on topic of your question.
ALLELOPATHY
http://www.aquariumplantsandsupplie...opathy-as-it-relates-to-live-aquarium-plants/


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## plantbrain (Dec 15, 2003)

Nate McFin said:


> Here is an interesing place to start on topic of your question.
> ALLELOPATHY
> http://www.aquariumplantsandsupplie...opathy-as-it-relates-to-live-aquarium-plants/


Except it does not occur near as anyone has shown in aquariums as to explain why tanks have no algae but non limiting ppm's.

I do large water changes, I add activated carbon, which removes the chemicals directly, and never get algae correlated with those two treatments. If alleloapthy really does occur, then I should see some effects, yet no one to my knolwedge ever has.

Most see the reverse observation: better plant growth, less algae.
This is also true for all plants/species, and the likelihood of all 300-400 species we keep all having the same effects on algae, and the same secondary allelopathic compounds that affects all species of algae are slim to none.

That's just the aquarist practical view, the research view is also similarly harsh.

In respect the poster:
There's a lot more to algae than nutrients.

The big 3: Light(too much typically), CO2(too little, or some folks go too far and gas their fish) and then............down on the list........nutrients.

Less light= less CO2 demand, so easier to manage, then nutrients are very easy. Most algae issues are related to high light/not enough.
Nutrients can cause algae, but this is most often due to too low(BGA, GSA etc).

Algae is general a function of poor growth of plants, EI provides a reference for non limiting nutrients. So then you can focus more on light, CO2 etc.......since you ruled out nutrients. Aquatic plant tanks would be easy if it was all about nutrients.

That's not the case however.
Regards, 
Tom Barr


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## Vaevictus (Mar 24, 2010)

Thanks for the replies. Interesting reading.

If what you are saying is true; assuming nutrients are not the limiting factor in photosynthesis in my tank, if I add high levels of nitrate, phosphate, Iron, magnesium, calcium, potassium, I will not increase an already existing algae problem? or cause one if none is present?


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## Hoppy (Dec 24, 2005)

Algae, once it is established in the tank, will grow better if well fed and well lighted. But, "well fed" for algae is a very tiny amount of nutrients. Algae have very low mass, even when ugly as sin in the tank, and they need almost no nutrients to get that big. Long before algae would be nutrient limited the plants would all starve to death. 

If you avoid lighting duration longer than 6-8 hours a day, that will help. And, most of all, if you decide to go with only medium light intensity (with at least moderate CO2 concentration), and slower plant growth, you will be making life a whole lot easier for you, but harder for the algae.


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## plantbrain (Dec 15, 2003)

Vaevictus said:


> Thanks for the replies. Interesting reading.
> 
> If what you are saying is true; assuming nutrients are not the limiting factor in photosynthesis in my tank, if I add high levels of nitrate, phosphate, Iron, magnesium, calcium, potassium, I will not increase an already existing algae problem? or cause one if none is present?


Adding to what Hoppy already well stated, the problem is not in the nutrients, the problem is that you are not focused on growing plants.

Poor plant growth=> algae is just a symptom of this issue.
So focus on the root issue, the plants. Algae is hardly an issue if that is done, then nutrients are very easy and there's few issues.

This is more likely too much light, not enough CO2 problem.
Read this instead since it is far more applied:

http://www.tropica.com/article.asp?type=aquaristic&id=142

Read it all and carefully.
Focus on light and CO2.
Then nutrients are really easy and plants grow really nice and there's no algae issues.

If you want to reduce anything to curb algae, it should be the light.
Then check the CO2 critically, then do a water changes, clean the tank, algae off, trim etc, clean filters etc.......then dose etc.



Regards, 
Tom Barr


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