# Dosing extra phospate- how much?



## pepedopolous (17 May 2014)

Hi there,

I've read about increasing phosphate dosing to help combat GDA and GSA. I'm just wondering what is a safe amount to add. I already dose EI (aquariumplantfood.co.uk starter kit). I have a 125 litre tank.

Recently I had a lot of GDA on the aquarium glass but I reduced the light, cleaned the glass, and it hasn't come back. However, I've always had a little GSA on the glass and there seems to be GDA still on the lower leaves of one plant in particular (_Staurogyne sp_.). I removed these leaves but GDA then appeared on the leaves that replaced them.

Cheers,

P


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## tim (17 May 2014)

I've found adding an extra teaspoon to my macro mix effective also look at lighting and flow if you dose dry an extra pinch or two won't hurt, unfortunately GSA is a bit of a curse with slower growers I tend to get it on anubias staurogyne and buces, but never crypts, go figure


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## pepedopolous (17 May 2014)

tim said:


> I've found adding an extra teaspoon to my macro mix effective



Thanks Tim. That sound's promising.

P


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## Sacha (17 May 2014)

I would be interested in the science behind dosing phosphate to combat GDA/ GSA. If we are dosing EI, there should always be phosphate in abundance anyway.


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## Jaap (18 May 2014)

I believe that according to Tom Bar, dosing extra macros or micros is not a problem at all. Furthermore,  the ratio of K N P is of no matter if none is limited. 

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## pepedopolous (18 May 2014)

Jaap said:


> I believe that according to Tom Bar, dosing extra macros or micros is not a problem at all



I don't doubt that. However, I'm not sure if I could simply add a pinch of dry potassium phosphate powder directly into a small (125l) aquarium. This would be a massive increase in the dose compared to EI.

The EI macro recipe needs only 1 teaspoon in 500ml of water, and then 10ml is added per 50l of aquarium water every other day.


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## tim (18 May 2014)

Sacha said:


> I would be interested in the science behind dosing phosphate to combat GDA/ GSA. If we are dosing EI, there should always be phosphate in abundance anyway.


Not sure on the science behind it, for me it rules out ferts and makes me sort out lighting, flow and co2.


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## Sacha (18 May 2014)

Are you implying that the standard EI formula does not contain enough phosphate?


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## tim (18 May 2014)

No, I have read on the forum to add extra phosphate to combat GSA, I am implying if that doesn't solve it it is probably down to over lighting to the co2 given.


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## Sacha (18 May 2014)

Right but I think you have missed my point. 

Two assumptions: 

1) the standard EI mix has the correct amount of phosphate

2) if dosing EI, we will always have an EXCESS of nutrients. 

According to these two assumptions, there is no reason to ever add extra phosphate. You will always have an abundance of phosphate- more than the plants could ever dream of using. 

So what I am asking is- where is the science behind this theory? Because the way I see it, adding more phosphate to water already full of phosphate isn't going to do much?


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## tim (18 May 2014)

Your assumptions are correct, IF correct ei levels are being dosed, my point is adding more will not cause problems, if GSA stops growing then you can assume you weren't dosing the correct ei levels and other parameters ie light, co2, flow are good, if it continues to grow then you need to look elsewhere ie light, co2, flow to overcome the issues.


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## Frenchi (20 May 2014)

I was just going to start a similar thread regarding EI dosing .. As I'm in the same predicament on my biggest tank.. I tried adding more phosphate and no change  .. I get a lot of beard algae but only at the top of my tank and it always seems to be in a flow area ? My co2 is everywhere in the tank so what I'm now on with is reducing the amount of Ei to see if there is just too much nutrient that is feeding algae instead of the plants ... I'm no expert though  ...  
Edit: it seems to be since I removed a few plants. 
Sorry for the hijack 

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## pepedopolous (20 May 2014)

No worries Frenchi! I think extra phosphates is only recommended against GDA and GSA. Also it may be irrelevant if you already dose EI, though I'm not sure. 

At the moment I'm adding more macro mix to get more phosphates in the aquarium. I don't get any more GDA on the glass but still a bit on some lower leaves, which are likely in a low flow area as well.

P


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## Frenchi (20 May 2014)

pepedopolous said:


> No worries Frenchi! I think extra phosphates is only recommended against GDA and GSA. Also it may be irrelevant if you already dose EI, though I'm not sure.
> 
> At the moment I'm adding more macro mix to get more phosphates in the aquarium. I don't get any more GDA on the glass but still a bit on some lower leaves, which are likely in a low flow area as well.
> 
> P


Seems like trial and error .. It is so frustrating though  


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## sciencefiction (22 May 2014)

I still find it hard to believe that GDA or GSA and certain other types of algae have anything to do with the plants. You can get it in non-planted tanks so what do you do then? Dose fertilisers in the water? Increase CO2?
The most likely problem is increased organics/ammonia because either your plants aren't happy for whatsoever reason and don't grow but this could be because of anything, too much light, lack of nutrients or certain nutrient deficiency or lack of co2, you name it. So what worked for one won't work for another most likely.

The other cause is that your filtration can't cope with the organic/bio load leading to increased levels. So obviously if you've done a huge trim your plants are less efficient at cleaning up the water so algae may appear. Same if you've removed your filter/filter media or washed your filter pretty well, adding way more fish, overfeeding, lack of water changes, too small water changes so organics accumulated,  etc..Or medicated the tank with meds that affect the bio-filter.


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## NatureBoy (22 May 2014)

I tend to find too little nutrition you get algae (often attacking the plants), too much nutrition you get algae and healthy plants (not attached to plants), just the type is different.

I've tried the excess approach and the limitation approach and both reveal problems that I don't get when I go for a low but daily addition, kind of going the way of an ADA approach


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