I need a little help with carbon dosing.

[Nano sapiens]

Certainly could be... The Siporax will likely only provide anaerobic conditions if it's not getting a lot of flow pumping through it. Is it possible to move it to a slower-flow area?

A sulfur denitrator has a minor disadvantage in that it will deplete alkalinity so you'll have to keep an eye on that and dose it if you're not already doing so, but it's a good option. There's no harm in using both nitrate reducing methods at the same time if you go that route. If you cut out carbon dosing altogether, beware that it should be done really slowly.

True, lowered alkalinity can happen if the flow is too fast due to the rapid production of H+ ions. If slow enough though, the alkalinity should remain steady.

Per 'The Reef Aquarium, Vol 3, pg 280' speaking to this steady alkalinity phenomena:

"It is thought that this is because the lower part of the reactor where the tank water enters is working as a heterotrophic area producing OH- ions (with the help of DOC from the aquarium)."

And still another way is to simply put a thin 3/16" layer of sulphur beads (used in the wine industry) with a layer of plastic screen on top covered by maybe three inches? of aragonite sand (can be placed in a display, but would be easier to install in a refugium). Under these anoxic conditions, the sulfur supply is used by denitrifying bacteria (they oxidize reduced sulphur to sufate while reducing nitrate (autotrophic denitrification). This type of denitrication doesn't need an external carbon source, so much less labor intensive compared to the heterotrophic methanol requiring denitrators. A bit experimental, but the method is mentioned in the 'The Reef Aquarium, Vol 3, pg 278'. I would expect that being a passive method that it would not reduce nitrate as quickly as a reactor would, but it's simple and relatively inexpensive.

 

[Jonify]

Microbacter7 or Vibrant will help pull your nutrients down, and once you get to the place you want, you can just start doing maintenance doses. Much easier than carbon dosing, and without all the risks. BUT, you will need a good skimmer for either option, just like with carbon dosing.

 

[Randy Holmes-Farley Verified Community Expert]

True, lowered alkalinity can happen if the flow is too fast due to the rapid production of H+ ions. If slow enough though, the alkalinity should remain steady.

Per 'The Reef Aquarium, Vol 3, pg 280' speaking to this steady alkalinity phenomena:

"It is thought that this is because the lower part of the reactor where the tank water enters is working as a heterotrophic area producing OH- ions (with the help of DOC from the aquarium)."

And still another way is to simply put a thin 3/16" layer of sulphur beads (used in the wine industry) with a layer of plastic screen on top covered by maybe three inches? of aragonite sand (can be placed in a display, but would be easier to install in a refugium). Under these anoxic conditions, the sulfur supply is used by denitrifying bacteria (they oxidize reduced sulphur to sufate while reducing nitrate (autotrophic denitrification). This type of denitrication doesn't need an external carbon source, so much less labor intensive compared to the heterotrophic methanol requiring denitrators. A bit experimental, but the method is mentioned in the 'The Reef Aquarium, Vol 3, pg 278'. I would expect that being a passive method that it would not reduce nitrate as quickly as a reactor would, but it's simple and relatively inexpensive.

Disagree. That cannot ever work out perfectly, and the claims are wrong, unless there is zero consumption of the sulfur.

The alkalinity lost in nitrification (ammonia to nitrate) is exactly offset by alkalinity addition in ordinary (organic carbon based) denitrification, making it a net neutral process from food to ammonia to nitrate and then denitrification.

Sulfur denitrification is a net alk depleting process. If you replace ANY of the ordinary (organic carbon based) denitrification with sulfur denitrification, the overall process will be alk depleting. If you pass the acidic, low alk effluent over calcium carbonate and get some to dissolve, you are just replacing the alk depletion with calcium boosting.

 

[Randy Holmes-Farley Verified Community Expert]

Microbacter7 or Vibrant will help pull your nutrients down, and once you get to the place you want, you can just start doing maintenance doses. Much easier than carbon dosing, and without all the risks. BUT, you will need a good skimmer for either option, just like with carbon dosing.

Adding bacteria does not always work. It may work in cases where natural bacterial are insufficient and organic matter is plentiful. That is not always the case.

 

[Nano sapiens]

Disagree. That cannot ever work out perfectly, and the claims are wrong, unless there is zero consumption of the sulfur.

The alkalinity lost in nitrification (ammonia to nitrate) is exactly offset by alkalinity addition in ordinary (organic carbon based) denitrification, making it a net neutral process from food to ammonia to nitrate and then denitrification.

Sulfur denitrification is a net alk depleting process. If you replace ANY of the ordinary (organic carbon based) denitrification with sulfur denitrification, the overall process will be alk depleting. If you pass the acidic, low alk effluent over calcium carbonate and get some to dissolve, you are just replacing the alk depletion with calcium boosting.

I see where you are coming from. However, per the aforementioned book:

'This hypothethsis has recently been confirmed by tests done by a colleague of Langouet's who added glucose to the sulfur reactor (and in doing so, increased the rate of heterotrophic reaction) and observed an overall increase in alkalinity (M. Langouet, pers. comm.)'

Interesting, perhaps something else was going on here that produced these results?

 

[Gordonm]

I know carbon dosing is a recurrent topic, but I've ran into an issue and I can't find a post that matches my situation and resolved it.

My tank has been set up for almost a year.
It's around 60g, contains a pair of large clownfish which I've had for around 12 years, a handful of snails and a few fungia.
I have a fine (0.5mm-1.0mm) shallow sand bed, and a ceramic scape.
The sump contains a theiling rollermat, bubble magus g7 skimmer, a carbon reactor, and 9 litres of siporax.
My parameters are:
Ammonia 0
Nitrite 0
Nitrate 50-60ppm
Phosphate 0.08
Alk 12.4 dkh (normally 10, but recently had a dosing mishap)
Magnesium 1350ish
Calcium 450

I began carbon dosing in August when my nitrate began to raise from 10-20 to 40ppm. I breed my clownfish and feed heavily to achieve large clutches of eggs, so wasn't surprised my 10% waterchange wasn't keeping up.

Since then my nitrates have gone up to 50-60ppm. I have been upping the dose a little a time, and believe that I have gone as high as I can. If I go higher, I get a bacterial bloom, but my nitrate remains the same.
I've done larger water changes, but nitrate just comes straight back within a couple of days.

I'm stumped, I've never had nitrates this high and I honestly don't know what I'm doing wrong?

I already clean the whole sandbed with every water change.
I think the denitrater might be my next step if the waste away doesn't help.
I've never had much luck with keeping algea alive long enough to export anything.

 

[Randy Holmes-Farley Verified Community Expert]

I see where you are coming from. However, per the aforementioned book:

'This hypothethsis has recently been confirmed by tests done by a colleague of Langouet's who added glucose to the sulfur reactor (and in doing so, increased the rate of heterotrophic reaction) and observed an overall increase in alkalinity (M. Langouet, pers. comm.)'

Interesting, perhaps something else was going on here that produced these results?

I'm not sure exactly what the experiment is, but two points come to mind:

1. That may be when one starts with high nitrate, not when one has steady nitrate. If you just use the glucose and no sulfur when you have high nitrate, alk will rise. Add in some sulfur denitrification and you could get an alk neutral process for a while.

2. Might mean alk in vs alk out of the reactor (which ignores the alk drop from ammonia to nitrate), not alk in the aquarium over time using that process and no alk additives.

 

[Gordonm]

I know carbon dosing is a recurrent topic, but I've ran into an issue and I can't find a post that matches my situation and resolved it.

My tank has been set up for almost a year.
It's around 60g, contains a pair of large clownfish which I've had for around 12 years, a handful of snails and a few fungia.
I have a fine (0.5mm-1.0mm) shallow sand bed, and a ceramic scape.
The sump contains a theiling rollermat, bubble magus g7 skimmer, a carbon reactor, and 9 litres of siporax.
My parameters are:
Ammonia 0
Nitrite 0
Nitrate 50-60ppm
Phosphate 0.08
Alk 12.4 dkh (normally 10, but recently had a dosing mishap)
Magnesium 1350ish
Calcium 450

I began carbon dosing in August when my nitrate began to raise from 10-20 to 40ppm. I breed my clownfish and feed heavily to achieve large clutches of eggs, so wasn't surprised my 10% waterchange wasn't keeping up.

Since then my nitrates have gone up to 50-60ppm. I have been upping the dose a little a time, and believe that I have gone as high as I can. If I go higher, I get a bacterial bloom, but my nitrate remains the same.
I've done larger water changes, but nitrate just comes straight back within a couple of days.

I'm stumped, I've never had nitrates this high and I honestly don't know what I'm doing wrong?

I had very high nitrates for years and could never get it down. Carbon dosing, water changes didn't make any difference. Then I finally tried bio pellets (can't remember the brand) and it slowly dropped over the next months to 1 ppm from 50.
Since then it's never increased .

 

[LilShaz]

I had very high nitrates for years and could never get it down. Carbon dosing, water changes didn't make any difference. Then I finally tried bio pellets (can't remember the brand) and it slowly dropped over the next months to 1 ppm from 50.
Since then it's never increased .

That's interesting. I hadn't considered changing my carbon source, I figured vodka was the same as vinegar etc, etc.. I'll definitely look into this, thank you.

 

[Gordonm]

That's interesting. I hadn't considered changing my carbon source, I figured vodka was the same as vinegar etc, etc.. I'll definitely look into this, thank you.

There called eco bak which takes care of the nitrates. Most I think just lower the phosphates. They are not cheap but worth the purchase if your having nitrate issues.

 

[malacoda]

I've not used Siporax, but I did use SeaChem De*Nitrate which is similar on my 20g. Seachem recommended 20-50 gph flow for De*Nitrate. Not paying much heed, I tried to simply use it passively in a mesh bag in my sump and it didn't do squat. Then I put it in a reactor that I ran ~35 gph through and within 48 hours it brought my NO3 down from 20ppm to ~1ppm.

That said, I believe too little or too much flow can have a huge impact on the amount of NO3 that the anaerobic bacteria in the micropores of the material are able to process.

IMO, it would definitely be worth checking with maker of Siporax to see if they recommend and specific rate of flow for optimal performance.

 

[Dan_P]

I know carbon dosing is a recurrent topic, but I've ran into an issue and I can't find a post that matches my situation and resolved it.

My tank has been set up for almost a year.
It's around 60g, contains a pair of large clownfish which I've had for around 12 years, a handful of snails and a few fungia.
I have a fine (0.5mm-1.0mm) shallow sand bed, and a ceramic scape.
The sump contains a theiling rollermat, bubble magus g7 skimmer, a carbon reactor, and 9 litres of siporax.
My parameters are:
Ammonia 0
Nitrite 0
Nitrate 50-60ppm
Phosphate 0.08
Alk 12.4 dkh (normally 10, but recently had a dosing mishap)
Magnesium 1350ish
Calcium 450

I began carbon dosing in August when my nitrate began to raise from 10-20 to 40ppm. I breed my clownfish and feed heavily to achieve large clutches of eggs, so wasn't surprised my 10% waterchange wasn't keeping up.

Since then my nitrates have gone up to 50-60ppm. I have been upping the dose a little a time, and believe that I have gone as high as I can. If I go higher, I get a bacterial bloom, but my nitrate remains the same.
I've done larger water changes, but nitrate just comes straight back within a couple of days.

I'm stumped, I've never had nitrates this high and I honestly don't know what I'm doing wrong?

What organic carbon are you dosing and how many mL / gallon?

 

[HB AL]

I know carbon dosing is a recurrent topic, but I've ran into an issue and I can't find a post that matches my situation and resolved it.

My tank has been set up for almost a year.
It's around 60g, contains a pair of large clownfish which I've had for around 12 years, a handful of snails and a few fungia.
I have a fine (0.5mm-1.0mm) shallow sand bed, and a ceramic scape.
The sump contains a theiling rollermat, bubble magus g7 skimmer, a carbon reactor, and 9 litres of siporax.
My parameters are:
Ammonia 0
Nitrite 0
Nitrate 50-60ppm
Phosphate 0.08
Alk 12.4 dkh (normally 10, but recently had a dosing mishap)
Magnesium 1350ish
Calcium 450

I began carbon dosing in August when my nitrate began to raise from 10-20 to 40ppm. I breed my clownfish and feed heavily to achieve large clutches of eggs, so wasn't surprised my 10% waterchange wasn't keeping up.

Since then my nitrates have gone up to 50-60ppm. I have been upping the dose a little a time, and believe that I have gone as high as I can. If I go higher, I get a bacterial bloom, but my nitrate remains the same.
I've done larger water changes, but nitrate just comes straight back within a couple of days.

I'm stumped, I've never had nitrates this high and I honestly don't know what I'm doing wrong?

I have a reef tank with lots of corals and fish, enough that I feed them 10 to 12 Hikari cubes a day, thus I have a large bioload. I stopped doing water changes 4 years ago and started dosing nopox then. I have around 85 gallons of water volume. To keep my nitrates between 5 and 15 I dose 20ml of nopox each morning. What kind of carbon are you dosing? Regardless you need to up your dose since the current amount is not enough for your system.

 

[LilShaz]

What organic carbon are you dosing and how many mL / gallon?

I have a reef tank with lots of corals and fish, enough that I feed them 10 to 12 Hikari cubes a day, thus I have a large bioload. I stopped doing water changes 4 years ago and started dosing nopox then. I have around 85 gallons of water volume. To keep my nitrates between 5 and 15 I dose 20ml of nopox each morning. What kind of carbon are you dosing? Regardless you need to up your dose since the current amount is not enough for your system.

I'm currently dosing 4.5ml of a 50:50 vodka and vinegar mix.

 

[LilShaz]

Thank you everyone for your help.
As we in the UK are in lock down again, it seems as though it's the perfect opportunity for me to give the system a little upgrade. I've decided to try both a large display refugium and a remote deep sand bed along with the carbon dosing.

I'll give the tank a couple of months to settle and let you all know whether or not it helps.

If anyone has any other ideas then please feel free to pass them on.
Thanks again,
Shaz.

 

[HB AL]

Sounds like good ideas

 

[Dan_P]

I'm currently dosing 4.5ml of a 50:50 vodka and vinegar mix.

You are under the carbon dose that really gets things going.

Near 1 mL/gal vinegar dose, bacteria slime and cloudy water can occur and nitrates start to drop. That is 60 mL for your system. Vodka, 40% ethanol, delivers more carbon per mL, so 7.5 would be an equivalent dose. I think that works out to be 3 ml ethanol.

At 4.5 mL 50:50 ethanol:vinegar, that is 2.25 mL ethanol and 2.25 mL vinegar or about 70% of the carbon dose to kick things off.

Also, you did not mention how accurately you are measuring the NO3 concentration. If you are not diluting the sample, you could be missing the fact that your NO3 is actually declining, and more carbon and PO4 might be what is needed.

 

[Seabiscuit]

I know carbon dosing is a recurrent topic, but I've ran into an issue and I can't find a post that matches my situation and resolved it.

My tank has been set up for almost a year.
It's around 60g, contains a pair of large clownfish which I've had for around 12 years, a handful of snails and a few fungia.
I have a fine (0.5mm-1.0mm) shallow sand bed, and a ceramic scape.
The sump contains a theiling rollermat, bubble magus g7 skimmer, a carbon reactor, and 9 litres of siporax.
My parameters are:
Ammonia 0
Nitrite 0
Nitrate 50-60ppm
Phosphate 0.08
Alk 12.4 dkh (normally 10, but recently had a dosing mishap)
Magnesium 1350ish
Calcium 450

I began carbon dosing in August when my nitrate began to raise from 10-20 to 40ppm. I breed my clownfish and feed heavily to achieve large clutches of eggs, so wasn't surprised my 10% waterchange wasn't keeping up.

Since then my nitrates have gone up to 50-60ppm. I have been upping the dose a little a time, and believe that I have gone as high as I can. If I go higher, I get a bacterial bloom, but my nitrate remains the same.
I've done larger water changes, but nitrate just comes straight back within a couple of days.

I'm stumped, I've never had nitrates this high and I honestly don't know what I'm doing wrong?

LilShaz, I have a nano tank and I use vodka for carbon dosing. I would use NoPox if I could afford it, but it is quite expensive here. You got me stumped too since it sounds like you've been dosing for several months. I can share with you how I knew when it started working for me. Two things stood out most as major changes. Soon after I started dosing, my waste removal from my skimmer changed from about 3mL a day to about 9mL a day. It tripled. Also, before I started dosing, I was consistently adding about 312mL of top off water a day (I set up a Jebao doser at 13mL per hour every hour. ) Soon after I started dosing, my top off water need decreased to about 72mL per day. That's about 4 times less fresh water than I used to use. I remember reading a denitrate chemical equation and it showed that H2O was being created in the process. I also went from cleaning my hob filter foam from once every 2 weeks to once every few days. Anyways, I was on pins and needles during the whole process since I wasn't sure it was going to work safely, but it did. I hope this helps.

 

[piranhaman00]

I just stopped carbon dosing after going slow for 4 months.

I had crazy white film growing everywhere, skimmers pulling out ***** stuff but nitrates didnt reduce.

The reason I stopped was insane cyano growth. Id rather just do large water changes periodically then look at a red tank.

 

[Randy Holmes-Farley Verified Community Expert]

I just stopped carbon dosing after going slow for 4 months.

I had crazy white film growing everywhere, skimmers pulling out ***** stuff but nitrates didnt reduce.

The reason I stopped was insane cyano growth. Id rather just do large water changes periodically then look at a red tank.

Cyano can consume organics, and is a potential concern. It is why I switched from vodka to vinegar: it caused less cyano.