Looking for thoughts on organic carbon dosing and nitrate

[biom]

Denitrification will not aiways create NO2 in the water. Only if it is incomplete. A well working system will transfer NO3 seemless into N2.

Sincerely Lasse

Unfortunately complete denitrification is less common than incomplete one. I am saying unfortunately because for me as environmentalist incomplete denitrification is of concern because of GHG emissions.
I doubt we managed somehow in our reefs to select only complete denitrificators, I think if there is denitrification happening it will be similar to the one happening in natural systems. I'm not saying NO3 will not be transferred to dinitrogen, I am saying it will probably involve more than one strain of bacteria (including non-complete denitrificators) and there will be intermediate products (such as NO2) of denitrification present and detectable in the water.

"Genome sequencing has provided a better appreciation of the distribution of denitrification genes among microbes. Complete denitrification, the reduction of nitrate to N2, is less frequent than partial denitrification among sequenced bacteria. Partial denitrification chains of nearly all possible arrangments have been found."

Denitrifying Prokaryotes

Denitrification is the dissimilatory reduction of nitrate to nitrogen gas. This respiratory process requires four enzymes that produce three obligatory intermediates prior to production of the terminal product. Denitrification is found in diverse array of microbes...

link.springer.com

 

[biom]

In this paper Lasse linked, it shows how NO2 produced can be very small even for large NO3 decrease (fig 2).

Thank you for summarizing this for me, really helpful.
You mean this Figure? I don't think Nitrite production it is very small at all. At the peak Nitrite nitrogen it is almost as high as Nitrate nitrogen. That is why I have asked Lasse if he measured Nitrite also during this process.

 

[taricha]

I don't think Nitrite production it is very small at all. At the peak Nitrite nitrogen it is almost as high as Nitrate nitrogen.

Note they had to do a different y axis on left for nitrate-N, and right for nitrite-N (1/5 as much).
And by the end of the 3hrs essentially of both no3 and no2 is gone. So totally plausible to detect only a trace of NO2 with Lasse sandbed denitrification system eating a bunch of NO3.

 

[taricha]

That is why I have asked Lasse if he measured Nitrite also during this process.

You gave me an idea...
That chart also implies that if what's happening is what we think is going on, then @Lasse could increase the flow through rate and maybe tweak the ethanol volume to try to maximize NO2 output just for fun.
It'd never be close to 1:1 in nitrogen (see chart) but it could be large compared to typical reef tank values.

 

[biom]

Note they had to do a different y axis on left for nitrate-N, and right for nitrite-N (1/5 as much).
And by the end of the 3hrs essentially of both no3 and no2 is gone. So totally plausible to detect only a trace of NO2 with Lasse sandbed denitrification system eating a bunch of NO3.

Yep thank you, different axis . Still significant IMO. In Lasse's real life case the process for reducing nitrate took more than 10 days and I would expect nitrite to be present in water for the same period, even a bit longer because there is offset.

 

[Lasse]

I'm currently on vacation. I will comeback in this issue when I come home next week. However - i do not think you can compare a natural system with one there you add extern DOC. I have not take any NO2 measurment in this rum. However - its easy to do a rerun

Sincerely Lasse

 

[biom]

So I did some data mining from the last 3 pages of @Lasse build thread. And I already considered Lasse's setup to be a best possible case - but crunching the numbers looks impossibly good.
Like 2 moles of Carbon removes 1 mole of Nitrogen, good.

Left chart is where I took different stretches of Lasse's data where he did various set volumes of 8% ethanol added fro a few days at a time.
When he doesn't dose any, NO3 climbs at between 2.5 to 4 ppm NO3 per day.
When he doses 18mL/day through his sand, NO3 drops around 2.5-3ppm per day.
The amount dosed is in mL of 8% ethanol (I interpret this as like 1/5 vodka) into 310L system.
The right chart is me trying to convert all those to moles/L of Carbon and Nitrogen.
(I'm not even sure that data is theoretically possible. Maybe Lasse can spot my error)


@Dan_P data with dumping vinegar into the water was more in the real world, like 40 moles C per 1 mole NO3 removed.

From what you have calculated here for Lasse's aquarium it looks dosing 1 ml of 40% vodka in 100L water will reduce nitrate with 3 ppm. Which is not something unusual for the "normal" vodka dosing. My very unprecise experiment showed similar trend - about 1-3 ppm nitrate removal per day for every 1 ml 40% vodka dosed in 100 L. (I dont have sump or deep sand bed).

From the paper with the figure it looks 1 ml 40% vodka in 100 L (fresh) water will reduce nitrate with about 7 ppm, which also is not big difference having in mind how special this experiment was (1,5 L sludge in 2 L water

 

[biom]

I'm currently on vacation. I will comeback in this issue when I come home next week. However - i do not think you can compare a natural system with one there you add extern DOC. I have not take any NO2 measurment in this rum. However - its easy to do a rerun

Sincerely Lasse

Enjoy your vacation Lasse.

 

[jda]

What is even being discussed here? No3 conversions with something else added?

30 years of feeding my fish with kilos of frozen food and 1/2/5 gallon buckets of pellets and .1 of no3 with a 3 inch undisturbed sandbed and I have never measured any nitrite. Ever. I did not even know that this was a thing. I have never needed to add any OC.

 

[biom]

What is even being discussed here? No3 conversions with something else added?

30 years of feeding my fish with kilos of frozen food and 1/2/5 gallon buckets of pellets and .1 of no3 with a 3 inch undisturbed sandbed and I have never measured any nitrite. Ever. I did not even know that this was a thing. I have never needed to add any OC.

We are discussing many topics here but most recently discussion is if there is denitrification happening in a reef tank in particular with organic carbon dosing. But your experience could help - which process keeps nitrates in your tank that low for decades?

 

[jda]

3 inches of sand. I don't use OC - never had the need. I could drop sodium nitrate in there in large quantities and the no3 level would be back down to a trace in probably a day.

 

[HomebroodExotics]

3 inches of sand. I don't use OC - never had the need. I could drop sodium nitrate in there in large quantities and the no3 level would be back down to a trace in probably a day.

What do you dose and feed your tanks?

 

[jda]

I just have a CaRx and change water. If I slack on water changes, I do dose some iron or else my chaeto slows down. That is all.

I feed pellets, flake, frozen many times a day. Auto feeder dumps pellets 4x a day in the main tank and side tank. I feed a lot. I speak more on this in my build thread.

 

[ReefGeezer]

3 inches of sand. I don't use OC - never had the need. I could drop sodium nitrate in there in large quantities and the no3 level would be back down to a trace in probably a day.

Do you think the corals and other organisms, besides those in the sandbed, play a major role in the efficient use of nitrogen in your system? I ask because that's what I am observing in my fairly mature mixed reef. I have almost no sand and a very high population of fish that are very well fed. I run my skimmer very dry. I have no Cheato or ATS, just a moderately sized cryptic fuge. I do have quite a few corals, sponges, tube worms, and etc. in the system that are growing rapidly. I find myself needing to add N to keep some measurable nitrate in the system.

 

[jda]

Probably. I do have chaeto and run 3x skimmers (good ones). I has never mattered. Even if I had only one skimmer and no fuge, the no3 would still be near zero at about .1-.2, or so. I only have the extra skimmers and fuge to keep po4 at a decent level.

I have a FOWLR with only an inch of sand and the no3 in that tank is also near zero. These fish are messy and eat a lot too. po4 is more of an issue in this tank with no fuge and only 2 skimmers.

Real porous live rock and also do the same thing as sand. I had a small angelfish that mowed down most of my sponges, but they are coming back. Those things, along with clams, can lower no3, IME.

I buy NLS pellets in the 5lb sacks and buy frozen food by the kilo. I feed a LOT. Always been a fan of heavy import and heavy export. Growing fish are non-aggressive fish, at least for me.

Nobody really had no3 issues with Dr. Ron was doing his thing talking about deep sand beds. I think that he mostly got it right, only that they do need cleaned every 3 or 4 years and do not need to be 6 inches deep. Don't get me started on the idiots that blame their sand as time bombs, etc... that is another thread for another day. Sand is good at lowering no3.

 

[ScottB]

I just have a CaRx and change water. If I slack on water changes, I do dose some iron or else my chaeto slows down. That is all.

I feed pellets, flake, frozen many times a day. Auto feeder dumps pellets 4x a day in the main tank and side tank. I feed a lot. I speak more on this in my build thread.

What iron supplement do you dose may I ask?

 

[ReefGeezer]

Probably. I do have chaeto and run 3x skimmers (good ones). I has never mattered. Even if I had only one skimmer and no fuge, the no3 would still be near zero at about .1-.2, or so. I only have the extra skimmers and fuge to keep po4 at a decent level.

I have a FOWLR with only an inch of sand and the no3 in that tank is also near zero. These fish are messy and eat a lot too. po4 is more of an issue in this tank with no fuge and only 2 skimmers.

Real porous live rock and also do the same thing as sand. I had a small angelfish that mowed down most of my sponges, but they are coming back. Those things, along with clams, can lower no3, IME.

I buy NLS pellets in the 5lb sacks and buy frozen food by the kilo. I feed a LOT. Always been a fan of heavy import and heavy export. Growing fish are non-aggressive fish, at least for me.

Nobody really had no3 issues with Dr. Ron was doing his thing talking about deep sand beds. I think that he mostly got it right, only that they do need cleaned every 3 or 4 years and do not need to be 6 inches deep. Don't get me started on the idiots that blame their sand as time bombs, etc... that is another thread for another day. Sand is good at lowering no3.

Tic-tic-tic... LOL

 

[Lasse]

I´ll start an experiment today. No DOC dosing for some days. NO3 today 2.3 and NO2 0.016 mg/L

Sincerely Lasse

 

[areefer01]

I buy NLS pellets in the 5lb sacks and buy frozen food by the kilo. I feed a LOT. Always been a fan of heavy import and heavy export. Growing fish are non-aggressive fish, at least for me.

Nobody really had no3 issues with Dr. Ron was doing his thing talking about deep sand beds. I think that he mostly got it right, only that they do need cleaned every 3 or 4 years and do not need to be 6 inches deep. Don't get me started on the idiots that blame their sand as time bombs, etc... that is another thread for another day. Sand is good at lowering no3.

Always amazed me how a lot of hobbyist only feed once or twice a day with very little each session. On a reef fish are constantly grazing and pooping. I've sense switched to hourly feedings dry with a healthy frozen in the evening and very happy.

 

[Lasse]

By mistake - the DOC dosing was not off last day - but I set it off today. NO2 readings

NO3 readings

Sincerely Lasse