# Ideal phosphate level???



## tetra73 (Aug 2, 2011)

Is there such a thing at all? 10 to 1 ratio to NO3??? http://www.plantedtank.net/articles/Fertilizers-in-a-Planted-Tank/1/

I always try to keep it around 5ppm. Any level lower than that I would see GSA really quick and even on plants like S repens growing near the substrate. With close to 50ppm of CO2 and medium high lighting, my tank consumes about 1ppm+ of phosphate per day. I try to keep the level around 5ppm but don't want to get too low to cause GSA. My tap water has about 2ppm but I use Phoslock to reduce it further near .5ppm, with my aged water. I want to make sure I add the right amount without having the existing phosphate in the tap water to screw up my reading or my phosphate level.


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## happi (Dec 18, 2009)

6:1 ratio worked well for me, seachem recommend 5:1 and i think TPN+ uses wide range of N ratio, i think the reason they do this because tps+ is dosed only once a week and our fish, food etc will add some po4. 

IME plant and soil could absorb 0.5-0.7ppm po4 per day


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## Hardstuff (Oct 13, 2012)

I use to live out on long Island myself but now I live in az. I cannot answer your question but if I had to guess 5ppms seems a little high but if your lighting is strong you may struggle a little more to keep it in the 5ppm range. I believe every tank is a different system so levels will vary. There are many factors like bio mass , lighting intensity , some plants consume more PO4 than others. You have to know your tank. 
50 ppms, thats a lot of CO2! I am guessing you do not want BBA growing or maybe had or have an issue?? I know its better to keep the levels up for that reason alone, but the livestock needs careful watching at higher levels. 
I never had BBA living in New York even with low levels of CO2. But since moving to AZ I have it growing in my soft water tanks. I know this thread is not about BBA but have you grown it in NYC area. Long Island deals with wells mostly & I never saw the stuff. I am starting to think it is a surface water issue. 
Sorry I could not be more helpful , but I think your onto it with the GSA growing when levels drop , mine grows GSA when PO4 gets low as well.


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## plantbrain (Dec 15, 2003)

I'm not sure there's an ideal level, certainly not a ratio.

I've had tanks do well with virtually none, other I could lard it on with reckless abandon. 

Limiting ppm's for one tank might be something very different for another.

I dose about 5 ppm per dose 2-3 x a week to a couple of tanks, one maybe .5 ppm.

Why?
The lower light, low demand, lower energy tank is fine either way.

Sediment can supply ample amounts if you use that as a source also.

Same with fish food/waste.

Depends a lot on the tank.

For a stemy higher light tank, 4-5 ppm seems to help and prevent GSA, particularly IF YOU HAVE GOOD CO2.


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## Greystoke (Jul 24, 2010)

In theory (according to Dr Redfield 1939), the natural balance between N and P is ≈ 16:1.
This translates to a NO₃/PO₄ ratio of 23, meaning that your PO₄ reading should be 1/23rd of your NO₃ reading.

It is claimed by a fair number of hobbyists that maintaining that ratio materially reduces the chance of an algae bloom.


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## tetra73 (Aug 2, 2011)

Hardstuff said:


> I use to live out on long Island myself but now I live in az. I cannot answer your question but if I had to guess 5ppms seems a little high but if your lighting is strong you may struggle a little more to keep it in the 5ppm range. I believe every tank is a different system so levels will vary. There are many factors like bio mass , lighting intensity , some plants consume more PO4 than others. You have to know your tank.
> 50 ppms, thats a lot of CO2! I am guessing you do not want BBA growing or maybe had or have an issue?? I know its better to keep the levels up for that reason alone, but the livestock needs careful watching at higher levels.
> I never had BBA living in New York even with low levels of CO2. But since moving to AZ I have it growing in my soft water tanks. I know this thread is not about BBA but have you grown it in NYC area. Long Island deals with wells mostly & I never saw the stuff. I am starting to think it is a surface water issue.
> Sorry I could not be more helpful , but I think your onto it with the GSA growing when levels drop , mine grows GSA when PO4 gets low as well.


No, I didn't grow BBA at all...they just decide to show up. In the past, they usually attack slow growing plants like crypts and on the substrates. I still see some but far from a major problem. I have a DHG carpet and currently working on growing a S repen carpet too. So, high CO2 is essential. I also have a 48" 2 bulbs T8 light and one 2 bulbs T5HO fixture. Total of 4 strips of bulbs...to get the par all around the tank as equally as possible on my 40b tank. Is a dirt tank and it was converted more than 4 months ago. It is running fine and no major problems. GSA is a persistent issue. The fish is fine since my CO2 level remains in the 40ppm and only reaching close to 50ppm by the end of the day.


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## Hoppy (Dec 24, 2005)

Greystoke said:


> In theory (according to Dr Redfield 1939), the natural balance between N and P is ≈ 16:1.
> This translates to a NO₃/PO₄ ratio of 23, meaning that your PO₄ reading should be 1/23rd of your NO₃ reading.
> 
> It is claimed by a fair number of hobbyists that maintaining that ratio materially reduces the chance of an algae bloom.


Unfortunately, a fair number of hobbyists also claim that phosphates cause algae, that nitrates need to be removed from the water, and that plants can "out compete" algae for nutrients. All of which are incorrect for aquariums.


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## mhuntley002 (Sep 12, 2013)

I keep phosphates at 4-5 ppm to soften the green spot algae that I've always seemed to have. This allows my ottos to eat it. No negative effects for me


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