DIY NOPOX and Nitrates

[JohnCisco]

Not sure if I should increase the dose of my DIY NOPOX based on my NO3 tests or continue as is for now, also don't quite understand the NO3:N ratio in my N-DOC result or maybe better yet why that and the N : C : P ratio should be when it comes to the chemistry of our tanks.

210 Gallon water volume mixed reef (SPS frags, acan colonies, other LPS and zoas)

I followed the home DIY recipe for NOPOX that was on here somewhere (been a while), I don't remember exactly the ratio but it was something like 40% vinegar and 60% vodka... at the time I was reading the thread when I mixed it.

So my NO3 has been reading high. Had been over 30 on a NYOS test kit. Got it down to around 12 with water changes but can't seem to get it to budge from there (2 months). I submitted an N-DOC test to Triton and it said my NO3 was 18 and my total nitrogen was 80: https://www.triton-lab.de/en/showroom/n-doc/3798
The N-DOC is showing an imbalance in my NCP ratio mainly just because N is so high, and the NO3:N ratio is off. Triton told me to use NOPOX to get my NO3 down first. I also already have my photoperiod on my fuge at 14 hours which is the most Triton recommends (I get this isn't a triton forum but just more info). I'm considering adding a second light. My chaeto is growing and I throw out a good chunk every 2 weeks.

My phosphorous is steady at 14, which is 0.04 PO4 (Hanna ULR and ICP gave me the same number)
But I'm dosing KH2PO4 at a rate to keep P between 11 and 16. If I don't dose it goes to 0.

I started dosing 16ml/day of DIY NOPOX 2 weeks ago and NO3 hasn't budged, I'm also dosing the maintenance dose per day of MicroBacter7 which is 5 drops per day, and feeding less. The observable difference in my tank these 2 weeks is the algae on the glass has slowed and the cyano I was experiencing is reducing. Good signs.

Should I stay the course with NOPOX or bump the dose up?
Been dosing 16ml DIY NOPOX going off the 2ml per 25 gallons. Should I bump up my dose to something like 3ml/25gal instead?

My thought is to leave it alone as I'm seeing positive signs in the tank even if the numbers on the test kit isn't coming down yet just thought I would see some movement on the test kit after 2 weeks. I got a Red Sea NO3 test kit just in case something was off with the NYOS and the RS is actually reading even higher at 32ppm but the NYOS is still showing 12. Maybe I just can't read colors though.

Any other comments about NO3:N and the N-Doc results I'm all ears too

thanks!

 

[Randy Holmes-Farley]

The N-doc test is "just for fun", IMO. There is no reason, either theoretical or empirical, that it should be any particular value. I'm also not sure it has much relationship to organic carbon dosing.

If nitrate is currently 12 ppm, I certainly would not increase the organic dosing. Too low is much worse than too high, and yours is fine, IMO.

 

[Lasse]

First - Triton report your total N content to be 18 ppm and after that calculate your NO3 concentration to around 80. In this case - they assume that all N lies as NO3. That´s not normally the case. For me - normally 50% of total N is from NO3 and the rest from all other N sources in the aquarium. If your measured 12 in NO3 is correct - 2.7 of your total N is in the form of NO3 and the rest (18,6-2,7 )15,9 mg/l is in other forms of N in the water column. I would expect that your NO3 test maybe show a too low level because of my experiences (more than 10 N-DOC tests) - NO3-N is normally around half the content of total N. But it can differ.

Because you dose organic carbon the ratio TOC/TC is of interest - it is perfect.

I think that most experiences with DOC dosing indicate that the first parameter to drop is PO4 and after a while - up to a month or more - NO3 will drop. IMO it is very important - if you already have begin dose PO4 - continue with this. If you do daily dosing - you guarantee a daily flux of PO4 through the system and the left over (concentration in water column) is not as important compared with no dosing .

The N-doc test is "just for fun", IMO. There is no reason, either theoretical or empirical, that it should be any particular value. I'm also not sure it has much relationship to organic carbon dosing.

If nitrate is currently 12 ppm, I certainly would not increase the organic dosing. Too low is much worse than too high, and yours is fine, IMO.

I have not same view here. For me - and my aquarium - the DOC testing have been a useful tool for fine tuning of my system. I get a second opinion of my alkalinity, I get total N (hence max NO3 level) I get a point of view of the relationship between inorganic/organic carbon - of importance if I need to dose DOC or not - or if I overdose. If I do not dose and if the relationship is steady - I get a hint that the internal transport/conversion to DOC works. I´m not so very interested of absolute figures - is the trend over time that interest me.

Sincerely Lasse

 

[JohnCisco]

ok I misunderstood the N:NO3 in the NDOC results then and makes me think my NYOS test is off and the red sea is more accurate, or I did something wrong/can't read colors.

The Red Sea NO3 did a test with yesterday, best I can tell it's 32, or a little higher but less than 64. This higher number would make more sense then.

I was not dosing NOPOX at the time of the NDOC test nor recently before it. I did the test because my PO4 was bottoming out and I started dosing PO4 then was getting some unwanted algae and cyano.... and not quite trusting my home NO3 test and unsure about how accurate my Hanna really was for reading P. Then got the results and after contacting Triton on how to make sense of it they just said to dose NOPOX to drive down my NO3, needed to get that in line before worrying about much else.

thank you both for the feedback, the NDOC isn't something I planned on doing often but just dealing with nutrient issues the past year trying to make sense of it all. Dosing the KH2PO4 has turned the tank around dramatically since Christmas for the better but trying to solve this cyano issue and some of the unwanted algae.

 

[Lasse]

The Red Sea NO3 did a test with yesterday, best I can tell it's 32, or a little higher but less than 64. This higher number would make more sense then.

Yes - and it will correspond to my experiences - 50/50 between other N and NO3-N

trying to solve this cyano issue and some of the unwanted algae

I was not aware of a cyano issue (or I normally refer it to cyano/dino issue). That change my point of view a little. IMO - use of organic carbon (and especially NoPox) can promote these issues. My first advise in Cyano/dino issues is always - stop dosing organic carbon source (dosing DOC) How to do in your case - i do not know but I would probably stop dosing DOC, keep on dose PO4 (up to 0.1 ppm) and let the NO3 issue be for the moment if it was my aquarium. When Cyano/Dino are under control - slowly start to handle the NO3 issue again

Sincerely Lasse

 

[Randy Holmes-Farley]

I´m not so very interested of absolute figures - is the trend over time that interest me.

I would say that is the "fun" part of my statement. It interests you. There is not a specific value that one might get that is clearly good or bad (IMO).

 

[JohnCisco]

When the kids are out of the house I hope to have more time and learn more about the actual chemistry and biology that's going on. Take some courses and whatnot. So interesting and not enough time.