# Phosphate deficiency



## Avalon

Please explain the effects of phosphate deficiency, given other nutrients are not deficient. Pics are welcome! I'll leave it open for interpretation; i.e., under various circumstances such as high light, low light, CO2, non-CO2...whatever you have to offer.


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## hoppycalif

The first symptom of PO4 deficiency I know of is green spot algae. I have grown some of that when I underdosed PO4 for awhile, but increasing the dosage to where it is now got rid of the algae right away. As far as I know that is a good way to spot a too low PO4 amount. Using the EI method of dosing would make it irrelevant what the symptoms are, since that method always keeps enough of all of the ferts in the tank.


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## yildirim

Hi,

PO4 deficiency will not only cause GSA but in case of all other nutrients exist in the water column it will cause many kinds of algal problems other than GSA. GSA may still occur even when you have 1-2 ppm of PO4 present in the column. So I consider PO4 as a cure for GSA not as a cause. 

Besides algal problems PO4 IMO is the main macro nutrient that has much influence on the plant growth and I observed increased growth at higher levels. But increasing PO4 requires greater attention than any other nutrients as even a small bit of increase may cause crashes at all other nutrients and CO2 as well. So one should always keep an eye on all nutrients when dealing with PO4 amounts.

YILDIRIM


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## Bert H

> GSA may still occur even when you have 1-2 ppm of PO4 present in the column.


 So Yildirim, how much PO4 are you typically carrying in your tanks? And if you don't mind sharing, what's your hardness, both kh and gh? I have a theory, regarding hardness and nutrient levels, totally unfounded, which I am trying to see if there might be any truth to.


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## yildirim

Hi,

I'm dosing 1,5 ppm of PO4 daily (I dose all other nutrients on daily basis as well) and aim 4-5 ppm present in the water column all the time. On water change days, I dose all the nutrients half more than usual. Even though I didn't make a rescent test of my water parameters, I'm pretty sure (because since a long time I dose the same amounts, carry on WC of 50% every sunday, and the parameters I 've tested did always remain the same since more than a year) that they are around:

pH:6,5-6,6
gH:10-11
kH:5-6

If you find out sth with your theory I would be glad to hear about that.

YILDIRIM


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## Avalon

yildirim said:


> But increasing PO4 requires greater attention than any other nutrients as even a small bit of increase may cause crashes at all other nutrients and CO2 as well. So one should always keep an eye on all nutrients when dealing with PO4 amounts.


Could you explain this in more detail? What are your observations of the relationship PO4 plays with NO3 and CO2?


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## taekwondodo

What I noticed (at work, so don't have my notes) is that when I had 20ppm+ of NO3 and no PO4 in my 55G, the NO3 would last for days. When I added PO4, my NO3 would drop like a rock and I had to add more to keep enough in the water column for the plants to use - I am assuming (unscientifically) that PO4 increases the plants ability to consume nitrate (and hence, grow better/faster/etc...).

I think what's being said is keep an eye on NO3 if you are adding PO4. If you run out of NO3 when you are dosing PO4 you could cause problems (could this be where/why the conclusions of the PMDD paper on adding PO4 came from?).

JMO (just my observation...)

- Jeff


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## Laith

I haven't done any testing to isolate the real cause but I have a sneaking suspicion that whenever I see premature leaf fall-off of older leaves it's due to a low level of PO4.

Every time I've noticed this I've also realized that the PO4 dosing was low. Perfectly healthy older leaf "stems" (where they attach to the rest of the plant) would suddenly melt and the leaves would detach...

Especially noticeable on Hygrophila corymbosa as well as sometimes Ludwigia repens.

On the other hand, the tank where I've seen this happen has liquid rock water so all sorts of strange things are possible.


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## yildirim

Hi again,

PO4 is the main macro nutrient determining the plant growth along with carbon. You all know that it is the nutrient that we dose in smallest amounts and the first and easiest to determine symptom for PO4 is stunted or very slow growth. If you do not have PO4 in the tank you may notice that all other nutrients remains nearly at same concentrations and plants can not use them properly and this is the main problem for poor water, stunted growth and nice algea. I have made several water tests daily to test the effects of PO4 on other nutrients and plant growth in the past and achieved my current dosing schedule specific for my tank. 

In the beginning I was so much keeping in mind to have the NPK ratios as mentioned in many posts in the fertilizing forum. But now I do not believe the necessity of any such ratios that much as there are many factors that may effect it. With the tests I have performed I have seen that with 1 ppm daily dosing of PO4, 4ppm of NO3 and 10ppm of K was sufficient. When I decided to up the PO4 gradualy I ended up with 2ppm PO4, 9ppm NO3 and 15ppm K daily. While suggesting this values I never considered the desired target values but instead respond of my plants and algea. Since a long time I do not even perform any water tests.

So, I can tell you that, which works for my setup, not guaranteed for everone;
1. Nutrient ratios for NPK are flexible and they are not to be obeyed strictly.
2. Daily dosing is very important for providing consistent values.
3. The target should not be to achive predefined values for nutrients.
4. The only indicator must be the respond you get from plants, fishes and algea. One should have to understand to interprete them before moving on with this hobby.
5. Having more nutrients present in the water is better than not having one or some or just on the edge for becoming defficient.

YILDIRIM


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