# Fe - PO4 versus Green spot algae



## Freemann (Mar 19, 2004)

I was thinking.
Lots of iron can cause green spot algae.
Phosphates remove green spot algae.
Iron interacts with phosphates and desipates.
Could we by adding phospates precipitate excess iron and thus eliminate spot algae?
Could we just do the same by reducing iron?
Just an idea. Comments?


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## plantbrain (Jan 23, 2004)

Freemann said:


> I was thinking.
> Lots of iron can cause green spot algae.


Really?



> Phosphates remove green spot algae.
> Iron interacts with phosphates and desipates.
> Could we by adding phospates precipitate excess iron and thus eliminate spot algae?
> Could we just do the same by reducing iron?
> Just an idea. Comments?


Nope, we can add chelated Fe, say DTPH versus gluconate. We also can measure Fe and see none's there after 3-4 days without adding PO4.

Likewise we can dose lots of Fe and little to no PO4 and still get GS.

If I do not add PO4, good CO2, I get green spot. I have never found any correlation between GS and Fe, nor any algae for that matter.

The previous myths suggested thread algae was caused by excess Fe.
We know thta's not true either.

Regards, 
Tom Barr


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## Avalon (Mar 7, 2005)

I gotta go with Tom on this one: I've never once had iron cause any kind of algae except when CO2 was too low, and I suspect dosing iron wasn't even the cause of algae.

From my observations, Green spot ALWAYS occurs when either PO4 is too low, or light is too high and you have not enough CO2. I experimented with the latter, just to see if Tom was BS'ing us (heehee). He's right...

I used to be plagued with GSA, thinking it was "normal" for high light tanks, and it was "OK," a byproduct of super-fast plant growth. 

Myth busted.

I no longer have any problems with GSA, but I have learned one thing: A heavily planted tank with high light, nutrients, & CO2 can really go through the PO4!


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## plantbrain (Jan 23, 2004)

Avalon said:


> I experimented with the latter, just to see if Tom was BS'ing us (heehee). He's right...
> 
> I used to be plagued with GSA, thinking it was "normal" for high light tanks, and it was "OK," a byproduct of super-fast plant growth.


I did also but I soon figured out it was CO2 many moons ago.
I notice many others had GSA, my Anubias were free though(I had high PO4 in the tap).

I fully encourage folks to try things for themselves and see. See if you can induce algae, if you know that, then you can get rid of it also.

Regards, 
Tom Barr


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## Sir_BlackhOle (Jan 25, 2004)

So what about on non c02 tanks? Will increasing po4 knock out the gs?


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## plantbrain (Jan 23, 2004)

If you follow simple non CO2 plant tanks methods, you seldom, if ever, have algae issues once stablished.

Having said that, you may dose PO4, NO4, Fe etc to a non CO2 tank, if the algae appears, and/or you have a low fish load etc.

Adding PO4, SeaChem Eq is a good idea, fish food alone causes deficicencies and the the nutrients provided help to off set the lack of these from fish food/waste in a non CO2 planted tank.

By adding these things, namely, K+, PO4, Ca/Mg, Mn/Fe, the tank can grow most any plant, unlike those folks that merely use fish waste alone............

You do not need to add precise amounts, just atad here and there weekly to relieve the limitation, growth is slow so you can get away without having to add alot and if the limitation does occur, you'll see it slowly develop and easily be able to respond by dosing a little more PO4/NO3/K+/Ca etc.

I dose once a week is all.
I have not ever had GSA nor needed to clean the glass in my non CO2 planted tanks for many months, typically 3-6 months.

Regards, 
Tom Barr


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## MissMinerva (Aug 16, 2004)

Is there a way to increase Po4 naturally? (meaning free!) I'm starting to get green algae on the glass on my 55 gal planted tank. Tank has been running about a year. I just moved June 1 so, did a good glass cleaning before setting up again.

Yesterday I tested and got the following - Ammonia 0 - Nitrites 0 - Nitrates 5-10 and Po4 1-2. Do these sound "normal"? I have no Co2, 80 watts Ultra Sun T8 flourescents (Cripes! They're bright!). I have been dosing Flourish Excel daily - 5-8 ml. hoping that the spot algae wouldn't appear again. Also a capful of iron supplement every so often.

I have quite a bit of Frogbit in this tank, thinking that that would suck up nutrients and help control the algae. But, now I'm wondering if I should remove it??? I have a pretty good fish load in there, including about 10 bristlenose juvies that are happily pooping their little hearts out. I actually was surprised that my nitrates were that low.

Anyway, should I try getting rid of some Frogbit? Or am I doing everything wrong? Also, I am on disability so, I need to keep expenses as low as possible!  

Thanks for any input!!!

Now that I look at the pic I just took, is the light too close to the tank? Could this be part of the GSA problem?


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## plantbrain (Jan 23, 2004)

Well you are using carbon enrichment............

Cheater

That's part of it......

Adding KH2PO4 will cost you all 5$ for life.
Feeding more is the other method.

I'm doubting the test kit measurements.....algae does not lie.

Add more Excel and add some PO4.
You can add 20mls every other day of Excel.
Also,add a little SeaChem Eq or Ca/Mg/K+.
Notmuch, just a 1/8-1/4 th teaspoon.
A smidgon of KH2POP4 once a week etc.

Regards, 
Tom Barr


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## Sir_BlackhOle (Jan 25, 2004)

I will try what you suggested. I havent had to clean the glass on this tank in over a year, but the anubias always have lots of algae on the old leaves.


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## MissMinerva (Aug 16, 2004)

plantbrain said:


> Well you are using carbon enrichment............
> 
> Cheater
> 
> ...


Thanks for the help, Tom. I think I can handle a pound of KH2PO4! For now I will increase the Excel and order from Greg as soon as I am able to. Do you think the Frogbit should go?

Jan


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## plantbrain (Jan 23, 2004)

Frogbit is a noxious weed in CA, so I kill it.
Then I grow it, then I kill it, then we go to the field and kill it.
WMD's, weeds of mass destruction.

Unlike the other WMD's, we can actually find and destroy these. 
Several folks suggested snails, the Neviticula's.

I collected a bunch in FL.
We will see if the native snails(these do not breed in SW/brackish) work well.

Regards, 
Tom Barr


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