# Purer forms of N without the K?



## HiNtZ (11 Oct 2017)

I'm looking to get N in my high tech but without also adding any additional K as I'm convinced the elevated levels are causing problems in my rotala. My fish load falls well short of the targets I'm looking to reach as it is so I'm looking for something to supplement. Any ideas?


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## Edvet (11 Oct 2017)

Ureum?


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## dw1305 (11 Oct 2017)

Hi all,





Edvet said:


> Ureum?


Yes, urea (CO(NH2)2) or ammonium nitrate (NH4NO3), but I'm sure you don't want to go down either of those routes.





HiNtZ said:


> I'm looking to get N in my high tech but without also adding any additional K


Other nitrates are available, calcium nitrate (Ca(NO3)2.4H2O), magnesium nitrate (Mg(NO3)2·6H2O) etc. 

cheers Darrel


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## HiNtZ (11 Oct 2017)

Thanks guys. Any particular reason why not the first two? 

Now magnesium nitrate really sounds like it would be right up my street, I'm adding between 8-10ppm Mgso4 each week because my tap is really really low. Any idea what ratio N would be going in at with a target for 10ppm magnesium?

Cheers


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## dw1305 (11 Oct 2017)

Hi all, 





HiNtZ said:


> Any particular reason why not the first two?


Just the ammonia. Urea is <"used by a few people">, mainly because the urea has to be converted to ammonia via biological action (by micro-organisms with the urease enzyme), but there are still risks involved.

Urea is very rich in nitrogen (46%), so you get a lot of bang for your buck.





HiNtZ said:


> Any idea what ratio N would be going in at with a target for 10ppm magnesium?


You can work it out from the RMM of magnesium nitrate, whatever it says on the container it will be the hexahydrate (Mg(NO3)2·6H2O) when you add it to the tank.

The RMM of the hexahydrate is 256.4 and Mg has a RAM of 24.3, and you have one Mg atom.
Nitrogen has a RAM of 14 and you have two nitrogen atoms, so 28.

28/24.3 ~ 1.15 and 1.15 x 10 ~ 11.5

This means that when you add 10ppm of Mg, you've also added ~11.5 ppm of N or (4.43 x 11.5) 51 ppm NO3.

The "4.43" figure is the RMM of NO3 (14 + (3*16) = 62) 62 divided by the nitrogen content N = 14.

cheers Darrel


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## HiNtZ (11 Oct 2017)

dw1305 said:


> Hi all, Just the ammonia. Urea is <"used by a few people">, mainly because the urea has to be converted to ammonia via biological action (by micro-organisms with the urease enzyme), but there are still risks involved.
> 
> Urea is very rich in nitrogen (46%), so you get a lot of bang for your buck.You can work it out from the RMM of magnesium nitrate, whatever it says on the container it will be the hexahydrate (Mg(NO3)2·6H2O) when you add it to the tank.
> 
> ...



Superb, thank you! I already used your calculations for mgso4 a while back.

11.5 ppm N along with 10ppm mg would get my week off to a great start. I can even still continue the rest of the week with kno3.

I'll order some now! Cheers!

Also, while I have you here.... Would dosing urea straight into the filter pick up minimise risks?


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## Daveslaney (11 Oct 2017)

Try Aqua Rebel Special N. I bought the pre mixed for convenience plus my tank is only 90ltrs so only dose 2ml daily but the mix is in the stickys at the top of this page if  your tank is larger and you want to mix your own. I dose mine at lights on when the PH is lowest when co2 is on.
The alternate sources of N make plants colour up real well.
I used to dose urea in my EI mix on the larger tank, replaced some of the No3 with urea 5g in 500ml mix.Same routine as above dose at lights on the results where really good.No problems at all.


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