Nitrate- cannot get it to fall

[CHSUB]

Ratios are a funny thing, I find them completely useless. In nearly all cases hobbyist are using hobby testing which are very inaccurate. If the nutrients are there the algae will consume them. Maybe in the ocean certain species over centuries will gain an advantage, however in a puddle of a reef tank over a couple of years or months?

What would the ratio gurus think of this ratio?

 

[Randy Holmes-Farley Verified Community Expert]

What would the ratio gurus think of this ratio?

I think nutrient ratios as reefing targets are basically an inappropriate waste of math.

I have never seen any reason to not just look at the individual absolute values to assess suitability.

In this case, the nitrate may be fine if there are other sources of N, and not fine if there are not. Since you know from experience with this particular tank that it works, then I expect there are adequate other sources of N. For folks who do not have that same experience with their particular system, I'd want to see nitrate higher.

The phosphate is OK. I'd prefer it a bit higher, but its not what I'd call too low.

 

[EnterName]

now the chaos is perfect:

We have Opinion A saying nutrient ratios matter, even in tanks with higher nutrient levels.

Then we have Opinion B saying nutrient ratios matter more when absolute values are low like in nature but less when they are a bit higher like in most reef tanks.

And now there is Opinion C saying they don't matter and absolute values are the most appropriate measure

I love it

 

[JonasRoman]

I think BOTH ratio and absolut values matter. Ofcourse I say, as N and P are the conductor of our tank, if I exaggerating a bit. The ratio in this example is approx 3.8, so very low, meaning its risk of N deficiency for the zooxanthelle/coral. The absolut value are fine I think.
Reason why ratio matters is that it tells me what will be limiting with further decrease, and here it will be the N. Also it tells me that when coral has used what it need for N there will be a waste of P, that maybe isnt ideal (but must not be bad). I would not lower P but rather have an eye on N and try to increase nitrogen input in that case.
Absolute values also matters, as in very hogh values, those can itslef be bad, where for instande very high no3 may be bad for the coral. Very high Po4 may inhibit calcification, etc.
So for me its both.

Jonas

 

[Randy Holmes-Farley Verified Community Expert]

The absolut value are fine I think.
Reason why ratio matters is that it tells me what will be limiting with further decrease, and here it will be the N.

I don't deny that possible value if one wants to know that. It's not trivial to use, however, since one would need to know in what ratio the values will decline.