# PO4 Limiting Fert = No algae?



## cbennett (Oct 20, 2005)

if you're getting that hard-to-scrub-off algae on the glass, then you need to add phosphate not reduce it. I had a horrible case of GSA until I started dosing phosphate.


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## Left C (Nov 15, 2003)

skiboarder72 said:


> I just found an interesting and detailed article on it, wondering if any of you have seen it, seems to contradict what tom barr and others have found with nutrients not causing algae growth
> 
> Control of Algae in Planted Aquaria
> 
> I am thinking about trying this because I am getting some annoying spot algae growth on the glass.


That article is 10 years old or older. Tom Barr has mentioned many times about some old "myths" being tested and were then found out to be not completely true. That's all I know about that.

I use rubber lip plecos for my green spot algae on the glass. They do a good job.

(I hold one of them by the dorsal fin and place it's sucker on the glass. Then I get my 9 volt battery and touch him with it every now and then. The glass is spotless in just a little while and the pleco has a fat little belly. You ought to see how fast his little rubber lips move when he gets the 9 volt treatment!!):icon_lol:

I'm just kidding. I don't do that.


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## epicfish (Sep 11, 2006)

Left C said:


> (I hold one of them by the dorsal fin and place it's sucker on the glass. Then I get my 9 volt battery and touch him with it every now and then. The glass is spotless in just a little while and the pleco has a fat little belly. You ought to see how fast his little rubber lips move when he gets the 9 volt treatment!!):icon_lol:



I actually have to use a 12V car battery. =/ Are my plecos broken?


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## skiboarder72 (Oct 13, 2006)

cbennett said:


> if you're getting that hard-to-scrub-off algae on the glass, then you need to add phosphate not reduce it. I had a horrible case of GSA until I started dosing phosphate.


the algae I am getting rubs off with a brush... but it is not blueish (its more greenish) I think it is great spot algae, I just put a bunch of PO4 in my tank and I'm going to see if it helps it out..

I have read tom barr's experments and they are very good and detailed, I just dont see how things could change... aren't aquariums the same from 10 years ago to now? their process seems very good to me!


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## Hoppy (Dec 24, 2005)

What changes is our knowledge. Most of what was "known" about planted tanks ten to 20 years ago was just myth passed on person to person until everyone assumed the myths had to be the true story. Even now most folks believe firmly that if they measure their tank water pH and KH they can figure out how much CO2 is in the water. But, at least almost all of us now understand that an excess of phosphates and nitrates, within reason, does nothing to encourage algae.


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## plantbrain (Dec 15, 2003)

The assumptions made where not valid it turned out.
So I made some new ones based on what I saw, which where counter to what was said and supported it fully.

It all starts with the observations, then you make some hypothese, then some test to see to these hypothese seem valid or not, repat the test and adjust as needed and then you can draw some conclusions

But test kit issues, the dosing required to do this, the low light of the test tanks and other factors, poor/misapplied literature support for the theory led to an incorrect theory, then it got amplified by the web exponentionally. 

As you can see, 10 years later we are still straightening folks out

Here's the simple thing:

We add it to a healthy tank=> no algae.
Folks with low levels=> have algae.
These observations exist over a wide range of parameters, hobbyists methods, tank sizes, various set ups, non CO2 methods, CO2 methods etc

Why accept what someone else has done when they have issues anyway?
Philips et al 1978 made some assumptions and this happened in the research side of things as well. Bachmann, Hoyer, Canfield et al straighten it out.

You add PO4 to a weed choked lake= you get more weeds, no algae.
Same deal here.

I took thigs a few steps further as I like to use algae as models for nutrients and the EPA even uses algae are bioindicators of nutrient pollution and issues in the environment.

BBA=> CO2 issue
GSA=> low CO2 or not enough PO4(2-3ppm is good)
BGA= low NO3 and/or high organic loading
Green Water => NH4
Staghorn => NH4 , urea

and so on.......

These algae are specific and bloom for defind reasons.
Such test set ups are repeatable for those wanting to grow and culture algae.

This is much more powerful and accurate in terms of management than a battery of test kits of which most are gross in their accuracy to just plain wrong. Uncalibrated testing is an issue that dates back 10 years or so in this hobby as well.

Other issues such as the CO2 being 10-15ppm back then(I'd been using 30ppm and knew it was okay and told folks to add more, many claimed that was bad for fish etc back then, funny how few say that today:hihi: ), very low NO3/poor test kits, fear of algae from dosing more traces, they had just started dosing K+ then and Mg.

Once folks started doing this, most everyone of them back then saw the error in the thinking.

Everyone had been adding enough NO3/K, GH, Traces,CO2, but the only thing missing was PO4.

So when they added that intensely limiting nutrient, they saw dramatic pearling like never before. Plants that had never thrived prior, now grew into weeds.

So you can try this and learn for yourself, try adding KH2PO4 at 2-3ppm a week. Add a bit more CO2.

That will rid you of that algae.

Regards, 
Tom Barr


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## Left C (Nov 15, 2003)

epicfish said:


> I actually have to use a 12V car battery. =/ Are my plecos broken?


Maybe you can try ODPC. That's short for *o*ver*d*riven *p*le*c*o.


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## skiboarder72 (Oct 13, 2006)

thanks tom barr, i appreicate everything you are doing for this hobby


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## RoseHawke (Mar 10, 2004)

Hoppy said:


> ". . . Most of what was "known" about planted tanks ten to 20 years ago was just myth passed on person to person until everyone assumed the myths had to be the true story. . . ."


Kind of like now, yes :hihi: ?


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## plantbrain (Dec 15, 2003)

Well, you make safe assumptions, look at the relevant primary research that is specifically applied, then make some hypothesis, test these with an experimental design, then repeat and be careful to properly isolate things, get the data, then draw the conclusions, you come out far better.

It is a myth that PO4 excess causes algae in a well planted tanks/lake etc.
We can test that.
We can see the results.

That was not done prior.
It's fairly straight forward.

Will this later be proven wrong?
I doubt it.

If your hypothesis is that "excess PO4 causes algae", at least do the justice to *test *things before drawing such conclusions.

You need to add only PO4 to the system and see.
Then you need to make sure the other nutrients are non limiting and that the system is otherwise stable prior to adding PO4.
Then you add various concentrations of PO4.

That was not done in that study.
I did it and Steve did it. Those folks have PhD's, I had a HS education at the time. It had nothing to do with education, just common sense, test and observations.

The assumptions I make tend to be fairly safe. I make a lot of mistakes before getting something right but I keep trying and experimenting, many, as we have seen time and time again, do not.

Then we get a myth..........
But.......that's not as rare as someone (generally a business after a market) using speculatory research comments such as Barley straw being the "miracle cure" for algae, or allelopathy etc, of PO4 limitation, Aqua Equalizer crystals, or charged Touramline minerals, or that clown that makes Penac.

Hopefully folks will question these more. They should be agressively challenged. I've yet to find any credence to any of them and very questionable research support....... if any.


Regards, 
Tom Barr


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## Hoppy (Dec 24, 2005)

A lot of times one of us will have a problem, and try a solution, and the problelm goes away!! Voila!! We have found another bit of scientific proof that our solution is the world's greatest. I do that. Unfortunately, a single instance of doing something followed by the problem going away does not demonstrate that the something was what fixed the problem.

But, each time we report our magnificent success, someone else will try what we did, and eventually enough people try it and find that it either is effective or isn't. Using Excel to get rid of some algae is one example - that one seems to be effective. Sticking willow branches into the tank to cure green water - that one seems to me to have been found to be much less effective.

My experiences with the ADA-style "drop checker" are another example, and one that has not yet really met the test of being successfully tried by a lot of people. But, if I kept the idea to myself, it would never even be tried.


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## andrewwl (May 3, 2004)

plantbrain said:


> So you can try this and learn for yourself, try adding KH2PO4 at 2-3ppm a week. Add a bit more CO2.
> 
> That will rid you of that algae.
> 
> ...


That's so inspiring. I can't wait to get home!


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## TINNGG (Mar 9, 2005)

Why does the Weird Al song "Everything You Know is Wrong" come to mind?

I think the phrase (which seems to be never used here) YMMV = your mileage may vary - comes to mind.

I had less algae issues when I was in a slump and neglected my tank. Go figure.


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## plantbrain (Dec 15, 2003)

YMMV for a reason, often the species of algae quickly tells me what is gouing wrong.

While there is user variation, there are general methods and trends that certainly do play a huge/significant/dominate role in the presence/absense of an algae bloom.

This is why consensus helps.
Not just anyone's opinion consensus, but those that are careful and know they have a certain amount of ppm's and good CO2 etc.
Some newbie, or an old timer stills cared to bump up their CO2, that's not a fair assessment.

When virtually everyone adds PO4 along with good CO2, KNO3, Traces,. GH etc, then things go along fine.

When someone assumes their CO2 is fine and still gets algae when they dose the PO4, is it the PO4's fault? No.

It's correlation, not causation, that's what hobbyists often do and think it means something more than it is. Many seem to think it's causation.

You tell me the species of algae, tank size, I can generally figure out what went wrong and how to fix it. My results seldom vary and actually have not ever varied much.

What has varied are assumptions the owner's of the tanks have made believing the test kits are infalliable, their readings etc or that their CO2 is perfect, or their flow circulation is fine, a million and one things, but the basic premise is very much correct, figuring out where each person that is not getting results after taking the general advice takes patience to tease apart where they went wrong.

We will find it, some get mad and give up too soon and dismiss everything.

But when folks have troubles and seemingly they have followed the right advice, often they have done something wrong somewhere.

Folks that have chronic algae issues(you know who they are) often are the worst to seek opinions from about curing algae:hihi: 

Think about that.

When they take your advice and still say they have issues, they missed something the rest have been doing.

Fortunately, there are defined reasons for these issues and algae are fairly consistent and removes a lot of the "YMMV".

Good plant "cures" algae issues.
Plants grow for defined reasons, if you still have algaem, re evaluate the CO2, the nutrients etc. 
EI takes care of the nutrients.
So all that is left really is CO2.

And we know how often folks have issues with that.......

Regards, 
Tom Barr


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## standoyo (Nov 6, 2005)

Since I have don't have quality reliable test kits, from my observations, a lot of things Tom says rings true.
Eg. CO2-runs out and I'm away on holiday for a week- all sorts of algae problems. brown, hair, BGA some signs of BBA.

I also noticed in PO4 limited aquaria the plants grow smaller and look thinner.
After adding a little PO4, the plants get really nice and bushy.
That said some of the hairy algae also grow bushy!
In this case, i already have a little hair algae to start with and the co2 levels were probably not high enough etc etc.

My two cents.


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## Momotaro (Feb 21, 2003)

Hemianthus micranthemoides seems to be a good PO4 indicating plant.


Mike


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