# Can some one translate this for me please. all chemical wotn



## GreenNeedle (13 Aug 2010)

Anglian water says that the drinking tap water contains:

13mg/l Nitrate
601Âµg/l P/l phosphorus
3.45mg/l Potassium

Now I assume the nitrate is 13ppm?  Tell me if I am wrong.

What on earth does the Phophorus one mean?  is it 0.6ppm?

Many thanks in advance.  I am just working out how much is being added from my 1 litre a day top ups on top of zero water changes.

AC


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## jfravn (13 Aug 2010)

*Re: Can some one translate this for me please. all chemical*

You're right. 1 Î¼g/l = 1 mg/m3. I.e. its 0.601 mg/l in your case.

Look here: http://www.ices.dk/Ocean/formats/Equivalences.htm


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## GreenNeedle (14 Aug 2010)

*Re: Can some one translate this for me please. all chemical *

so in the case where we dose ppm of phosphate what does that translate into or are we looking for phosphorus ppms out of the phospahate.  Sorry to sound like a newbie but I've never really taken any interest before. lol

AC


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## ceg4048 (14 Aug 2010)

*Re: Can some one translate this for me please. all chemical*

Andy,
       It depends on who is doing the calculation and what frame of reference is being used. For our purposes, we don't bother to calculate the N due to NO3 (displayed as N-NO3) or the P due to Phosphate (P-PO4). We just use the NO3/PO4 concentrations and call it good.

Sometimes, biologists or chemists want to know the N contribution of NO3 because perhaps there are other sources of N in the sample being measured such as NH4, so they need to know the amount of N being contributed by the NO3 alone versus the N being contributed by the NH4. 

This is just a simple calculation since the N is only 23% by weight of NO3. There are 3 Oxygen atoms for every Nitrogen in this ion. So Oxygen is 77% by weight. So if you see a number like 10ppm N-NO3 then 10ppm is only the Nitrogen concentration and is 23% of the total NO3 concentration. To find how much NO3 concentration was responsible for 10ppm of N you would do the following calculation:

10ppmN = 0.23*(NO3) => 
Divide by 0.23 to isolate NO3 => NO3=10ppmN/0.23  =>
NO3=43.5ppm

So it takes 43.5ppm of Nitrate to generate 10ppm of N from that Nitrate.

Instead of doing algebra every time, 1/0.23 (or punch this in on your calculator to get 4.35) becomes the conversion factor to change N-NO3ppm to simple NO3ppm, and conversely, multiply the NO3ppm by 0.23 to figure out how much Nppm there is.

You can do a similar computation with P-PO4 knowing that P is about 33% by weight of the PO4 molecule. So  without slogging through the algebra again you can guess that the conversion factor is gonna be 1/0.33 or 3.0 depending on which direction you want to convert.

Again, since we dose the molecules NO3/PO4 and then let the plant figure out the algebra, we really don't care about N-NO3 or P-PO4 - but we can always figure it out if we need to.

Hope this helps.  

Cheers,


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## Mark Evans (14 Aug 2010)

*Re: Can some one translate this for me please. all chemical *

just what i was thinking Clive   just didn't know how to express it in words. well done.   

Clive mate, incredible knowledge...The mod who makes a difference!


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## GreenNeedle (14 Aug 2010)

*Re: Can some one translate this for me please. all chemical *

indeed. thanks very much Clive.

It isn't that I am trying to work anything out for a valid reason or to use the figures.

I was just wondering because I don't do water changes anymore but do top up the water every day, so I add about 1% of the tank water daily and therefore some goodies with it.  I then add 1.5ml of my macro mix (from EI previous) whenever I see green spots start to form on anubias so we are talking every 3-6 weeks.

Just wondering how much I am 'dosing' even though it is such a tiny figure 

Thanks for the info

Regards
AC


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