# What is everyone P04 levels in your planted aquarium.



## thunderjack14 (Nov 28, 2014)

Hello everyone !

I would like to know what people's readings are for po4 levels in a high tech planted aquarium. Why i ask is because im running at 5.0 ppm now because i'm trying to get rid of green spot algae and i did a lot of reading on forums and got a lot of feedback that it's because i'm bottoming out on PO4 levels i was around 0.25 to 1 ppm. I used dry fertilizers kh2po4.

Second question whats the maximum PO4 levels before it starts to affect the fish?

I have a feeling it's my levels of po4 because i run my t5 lights on a timer only 5 1/2 hours a day down from 8 hours a day and still got green spot algae and co2 is at 30 to 35 ppm all the time it's set up to a ph controller set at 6.6 ph. does pps pro on a dosing machine every day at the same time one hour before light on and only 15 ml of macro and micro on a 150 gallon aquarium to me that not much fertilizer. 

Thanks in advance everyone.


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## Zapins (Jul 28, 2004)

1 to 2 pm for me.

Green spot is not directly linked to PO4 levels. That is an unproven myth. Algae is more directly related to unhappy plants. The better plants grow the worse algae does. That is why temporary nutrient defficiencies (including PO4) can weaken plants and give algae a chance to grow.

Just focus on providing adequate nutrients to the plants and algae will work itself out.


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## thunderjack14 (Nov 28, 2014)

Hello Zapins!

Thanks for the fast reply.

OK so that sound like where my gsa is coming from my po4 was to low and the plants could not utilize the no3 in water column there for plants getting weaker as time went on and the algae was taking over.

My no3 after water change was 5 ppm and po4 was 0.25 ppm as my no3 go's up by the end of the week i'm at 10 ppm of no3 and po4 are still at o.25 not the right ratio. 

Hope that's right

Well thanks for clearing this up for me zapins and showing me the light lol lol


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## Zapins (Jul 28, 2004)

PO4 might have been the issue but if you were reading 1-2 ppm then I don't think it was.

Low nitrates might have caused the plants to weaken and caused the algae.

Also, ratios aren't as important as many people think. Plants will grow well in a large range of conditions and it doesn't really matter if the ratio is 1:4, 1:10, or 1:100.

The only two things that are very important are that both nutrients remain abundant enough to be seen and absorbed by the plant and that both nutrients do not run out as the plant uses them up. In other words if you have 1 grain of sand worth of a nutrient in the ocean that is below the amount that a plant can detect and absorb and so that basically counts as 0. And of course if you don't replace the nutrients as they run out they will eventually... run out.

Have a read through this article I wrote a few years ago. I brought together a lot of these ideas to explain how deficient plants cause algae: http://www.aquaticplantcentral.com/forumapc/algae/98538-algae-nutrient-deficiencies.html


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## Solcielo lawrencia (Dec 14, 2016)

GSA is not caused by low phosphates. In my experience, it has a lot to do with excess trace nutrients. If dosing excess traces - either EI, PPS, or dosing when plants indicate no need - the excess will be used by bacteria/GSA as a nutrient supply.

The best way to reduce traces is to not add excess to begin with. Adding high concentrations of phosphates can cause precipitation which also reduces them and can eliminate them once there, hence this commonly observed correlation. High oxygen concentrations increase oxidation rates which can also render the metals unavailable.

I usually keep PO4 around 0 to 0.5mgl and don't get GSA unless I overdose traces.


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