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Discussion Starter · #1 ·
I've read that an estimated ratio of 10:1 seems to work pretty well for N:p, at least as a starting point...

But now I have a doubt: are we talking about N & P or NO3 & PO4? :?
 

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I think it can be used for both probably. I mean NO3 is what we dose to provide N for the plants, we don't really look at other nitrogen sources such as ammonia, and PO4 is what we use as a source of P, so it should be valid for both if that's what you are dosing to provide these two elements, at least in this context.

Giancarlo Podio
 

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Laith said:
are we talking about N & P or NO3 & PO4? :?
Yes, this is confusing. Some research been done with N:p and some with NO3:pO4.

N:p of 10:1 = NO3:pO4 of 10:0.69

Usually, in this hobby, we use NO3:pO4 because our test kits measure NO3 and PO4. In practice, ratio NO3:pO4 of 10:0.69 works great for plants. Keeping it that way is another matter. To maintain this ratio in the water column, dosing NO3:pO4 of 10:1 to 10:3 is needed.

Edward
 

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well, if you adjust Edward's 10:.69 ratio you get 15:1 N:p. Maybe that has nothing to do with it:)
 

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Yeah Dennis, it was acutally 15 not 16.

But isn't the 10:1 for NO3:pO4 and 15:1 for N: P? Edward had it the other way around.
 

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MOST of the submersed aquatic macrophytes(SAM) have a ratio of 10:1 N:p.

We dose NO3/NH4 and PO4.

16:1 comes from algae, the redfield ratio , we are not growing marine phytoplankton last time I checked here which is what Refield was looking at.

Issue number #2.

Plants might have this ratio for many reason's out in nature, they might have far more or less depending on if they are limited and in terms of luxury uptake, perhaps even 100X more/less.

I still feel ratios are fine but have a very wide range in most cases.

Regards,
Tom Barr
 

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My htinking about ratios is that they are only important to you. I feel, at lesat so far inlmy limited experience, that a tank seems to have a raatio that it likes. That ratio may or may not work for another tank and if it works, it is mearly chance. I agree that there is probably a range of ratios that will cover most tanks but yuo will still need to tailor you specific one, that may change over time.
 

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It is a moving target certainly.
So if you want to approach it, you may want to try out a variety of ranges after getting a good feel.

But.....make sure you keep the other variables in line while you play with one or two etc.

That will give you much better results and allow you to see the effects much more clearly.

It'll also force you to do well with CO2, lighting, NO3 etc while messing with say... PO4.

There is a method to the madness in what I suggest.
The goal is to prove something to yourself, not me.

Regards,
Tom Barr
 

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Discussion Starter · #12 ·
Now I'm even more confused :?

So the 10:1 ratio is N: P (as per Edward and Tom)?

Therefore, the NO3 : PO4 ratio is 15 or 16:1?

Or do I just take a number in between as a baseline? :D
 

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Laith,

The lower the fish load/feeding, the lower the ratio needs to be. I feed lightly and have only moderate fish loads so I started witha ratio of 8.5:1 N/P I am now dosing ~20ppm N and 3ppm P a week, a ratio of about 6.7:1. HTis is a change that I have worked to over the past few months, mainly by just increasing my NO3 dosing to try to keep it from bottoming out. That is a good bit of P and I know that some might question this but I am mearly experimenting and learning. I am trying ot find my limits a my tanks limits. HTis is of course in one tank I have. The others are all different. Yours will not be like mine. The most important thing you cando for your plants, and to keep out algae is to make sure that [email protected] is 30ppm and that your NO3 neverhits 0ppm. Keep these up for a couple weeks where they belong, dose P 1-2ppm a week and dose plenty of trace. Keep this up for 2-3 weeks thenif you want start playing with your ratios. The only resaon to adjust is to try and make your life easier, lower P means less N use, slower growth, less trimming, etc, as does lower light Tom:), or to try and bring out the red of plants like Ludwigia or Rotala, etc. by having a balanced lower N.

Hope that rambling helped
 
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