Carbon dosing causes STN/RTN

[Kruss7]

Hi everyone,

I wanted to share my recent experience with carbon dosing and its impact on my SPS corals, specifically Acropora. I've been keeping SPS for many years, and my system is a 300-gallon SPS-dominated tank. Here are my parameters:

Salinity: 35ppm
Alkalinity: 9 DKH
Calcium: 450 ppm
Magnesium: 1400 ppm
Nitrate: 25 ppm
Phosphate: 0.06 ppm
pH: 8-8.2
Temperature: 78.5°F

As a background I consistently change my RODI filters and monitor alkalinity with an Alkatronic and a Trident, referencing a Hanna checker. I check other parameters with Hanna and Salifert kits and regularly recalibrate my pH probe. My system has a lot of flow (3 MP60s, 4 MP40s) and light (4 Orphek Atlantik V4s and OR3 bars). I maintain stability with a calcium reactor and kalk to boost pH, and I use a filter roller. I dose trace elements with the Captiv8 line and have just sent out an ICP test to double-check my levels. I don't run GFO or a reactor but use an algae scrubber and do weekly water changes with Reef Crystals to remove detritus.

Recently, I noticed my nitrate levels creeping up, starting at 15 ppm a couple of months ago and increasing by 1 ppm every few weeks. To get it under control, I began carbon dosing with vinegar, following the dosing chart and slowly ramping up over a couple of weeks. Despite reaching 100 ml per day, I saw no reduction in nitrate or phosphate. However, I did notice some of my previously happy SPS corals started peeling in the middle with their polyps out.

This is the second time I've experienced this with carbon dosing. (I am using vinegar) The first time, I thought it might be a coincidence, but now I'm convinced there's a correlation. I've stopped carbon dosing and noticed a bit of cyano on some frag plugs and dead tissue, which I never had before. I suspect that carbon dosing might be promoting the growth of bad bacteria, leading to STN or peeling in my SPS corals.

I know that carbon dosing works wonders for some reefers, likely because they don't have harmful bacteria strains present in their systems. For those who have success with carbon dosing, it can effectively reduce nitrates and phosphates by enhancing beneficial bacteria activity.

To address the issue, I'm now focusing on increasing positive bacteria strains in my tank by dosing beneficial bacteria to help outcompete the harmful bacteria. I'm hopeful this approach will stabilize my system and prevent further issues.

Has anyone else experienced similar issues with carbon dosing? I'd love to hear your thoughts.

Thanks!

Below was my sps a couple days ago. Great colours to what is now happening.

 

[bubbgee]

How do you dose it? Do you use a sump? I dose bactobalance in the sump instead of the display. Maybe the concentrate irritates the tissue when it touches the sps directly?

 

[Kruss7]

How do you dose it? Do you use a sump? I dose bactobalance in the sump instead of the display. Maybe the concentrate irritates the tissue when it touches the sps directly?

I’m dosing vinegar as a carbon source. It’s dosed as little as possible as many times as possible on a dosing pump into my first chamber of a 80 gal sump. Has tons of time to mix in the sump before going to the display. I really wish this was the answer.

 

[bubbgee]

I’m dosing vinegar as a carbon source. It’s dosed as little as possible as many times as possible on a dosing pump into my first chamber of a 80 gal sump. Has tons of time to mix in the sump before going to the display. I really wish this was the answer.

Dang. Can you rule out a contaminant in the vinegar? Or are you using a brand of vinegar that was recommended and used by others?

 

[Kruss7]

Dang. Can you rule out a contaminant in the vinegar? Or are you using a brand of vinegar that was recommended and used by others?

I cannot rule that out, but this is a different brand than the first time I had this happen. It is the same type of vinegar that I have seen recommended, just a different brand. I really believe I have a bad bacteria that it accelerated the growth of.

 

[Miami Reef]

Sorry to hear that. :(

Definitely stop dosing it. The corals should (hopefully) quickly recover once the vinegar source has been consumed.

Once they recover, you can try using a refugium or algae scrubber. Switching to other carbon sources like Vodka or Bacto Balance, and ramping very slowly, are other options.

 

[Kruss7]

Sorry to hear that. :(

Definitely stop dosing it. The corals should (hopefully) quickly recover once the vinegar source has been consumed.

Once they recover, you can try using a refugium or algae scrubber. Switching to other carbon sources like Vodka or Bacto Balance, and ramping very slowly, are other options.

Very annoying, but hopefully it turns around. Last time it took a few weeks but I thought it was a coincidence.

Think water changes would help right now? Or just let it play its course with beneficial bacteria?

 

[Miami Reef]

Very annoying, but hopefully it turns around. Last time it took a few weeks but I thought it was a coincidence.

Think water changes would help right now? Or just let it play its course with beneficial bacteria?

Acetate will get rapidly consumed. Once you stop adding it, there will quickly be little trace left.

The bacteria populations will dwindle down by itself. As long as you don’t add anymore, I predict the corals will bounce back fairly quickly, as long as they haven’t completely died.

 

[Jasonak]

Firstly your coral looks amazing!
Carbon dosing promotes the growth of all bacteria good and bad.
Ive struggled with STN and RTN I do not want to jinx myself but it seems that since ive ran up my nitrates that this has seemed have stopped. My Nits are at 28 as of yesterday. My phosphates were way up at .5 and im brining them back down. I started carbon dosing and adding bacteria in hopes to fight my STN/RTN a few months ago but started having problems with cyano so stopped. Ive been dosing ammonia for little over a month and my tank is best its ever looked with really amazing growth. I only carbon dosed with biofuel and bacto balance and I already had a pretty bad random STN/RTN problem months before I started that. So actually im probably not much help to you other than to say that I would not worry about Nitrates at 25.

 

[Kruss7]

Acetate will get rapidly consumed. Once you stop adding it, there will quickly be little trace left.

The bacteria populations will dwindle down by itself. As long as you don’t add anymore, I predict the corals will bounce back fairly quickly, as long as they haven’t completely died.

Let’s hope! It’s only 3 acros that have any negative effects so far. One tiny frag of one of my colonies instantly RTNed, a Marvin the Martian peeled almost completed overnight and a wild colony has some STN but is holding on so far. Everything else seems so healthy. But so did they yesterday.

If this goes away in the next day or so and I only lose that I’ll be okay, can trade for a couple replacements when stuff settles down.

I really think this is the cause, it’s the only thing I’ve changed, but I’ve sent an icp just in case. I even got my Rodi water tested this time.

 

[Kruss7]

Firstly your coral looks amazing!
Carbon dosing promotes the growth of all bacteria good and bad.
Ive struggled with STN and RTN I do not want to jinx myself but it seems that since ive ran up my nitrates that this has seemed have stopped. My Nits are at 28 as of yesterday. My phosphates were way up at .5 and im brining them back down. I started carbon dosing and adding bacteria in hopes to fight my STN/RTN a few months ago but started having problems with cyano so stopped. Ive been dosing ammonia for little over a month and my tank is best its ever looked with really amazing growth. I only carbon dosed with biofuel and bacto balance and I already had a pretty bad random STN/RTN problem months before I started that. So actually im probably not much help to you other than to say that I would not worry about Nitrates at 25.

Thank you! Hopefully I can keep them looking like that lol.

I just didn’t want them to creep any higher but I definitely regret it now. Going to try and worry less about it, maybe just do more larger water changes in future.

 

[Jasonak]

Thank you! Hopefully I can keep them looking like that lol.

I just didn’t want them to creep any higher but I definitely regret it now. Going to try and worry less about it, maybe just do more larger water changes in future.

I feel your pain, ive did the aquabiomics many ICP test and could not find anything wrong. It would affect everything from montis to acros be from slow to fast it was so frustrating. Ive set up a Lowboy now to start making copies of everything as insurance. At this point ive gave up worrying about it. But it is nice that I havent had any casualties as of late. :)

 

[Kruss7]

I feel your pain, ive did the aquabiomics many ICP test and could not find anything wrong. It would affect everything from montis to acros be from slow to fast it was so frustrating. Ive set up a Lowboy now to start making copies of everything as insurance. At this point ive gave up worrying about it. But it is nice that I havent had any casualties as of late. :)

I have a lowboy as well for this reason. 2 systems definitely offers a safety net. Fingers crossed your stuff stays good!!

It’s so weird how my other acros are still so happy, great colour and polyp extension.

It’s also weird how those are peeling with polyps out. Acros are so annoying lol

 

[bubbgee]

From my experience, Marvin the martian is my canary in the coalmine for any flow issues. Like a clogged/dirty powerhead leads to it having less PE and then closed. Wild colonies and small frag that RTN for me are usually from flow or ALK swings.

Just food for thought.

 

[Biff0rz]

My setup is almost 1:1 with yours. I dose 13ml/day of carbon (vodka from costco). Zero issues.

If I was dosing 100ml/day that'd be quite significant. Imo if you're dosing that much something else is up. Either nutrient export isn't working well (skimmer aint skimmin) or you've got detritus built up somewhere that needs a good cleaning (sump perhaps?)

I do dose 'good' bacteria once in a while, when I do, this is what I use, it's good stuff: hxxps://www.amazon.com/dp/B009NA5TYA

 

[Kruss7]

My setup is almost 1:1 with yours. I dose 13ml/day of carbon (vodka from costco). Zero issues.

If I was dosing 100ml/day that'd be quite significant. Imo if you're dosing that much something else is up. Either nutrient export isn't working well (skimmer aint skimmin) or you've got detritus built up somewhere that needs a good cleaning (sump perhaps?)

I do dose 'good' bacteria once in a while, when I do, this is what I use, it's good stuff: hxxps://www.amazon.com/dp/B009NA5TYA

You are dosing roughly 104 ml a day of vinegar. Vodka is roughly 8x stronger.

I honestly never noticed any decrease from it, it’s not like my nitrates are flying up fast either, I even clean my sump every other week.

I’ve heard really good things about those from other old school reefers near me. I’m gonna have to give it a try.

 

[Biff0rz]

You are dosing roughly 104 ml a day of vinegar. Vodka is roughly 8x stronger.

I honestly never noticed any decrease from it, it’s not like my nitrates are flying up fast either, I even clean my sump every other week.

I’ve heard really good things about those from other old school reefers near me. I’m gonna have to give it a try.

Yea, I'm not sure what the conversion is, but you're probably right. When I take my carbon offline, my nitrates, currently 10-15, will jump to 20-25. You're definitely more diligent about maintaining your sump than I am. I clean it *maybe* once a year...maybe lol.

I think there may be cheaper sources of it, it is kinda pricey, I haven't looked lately.

 

[Pistondog]

Hi everyone,

I wanted to share my recent experience with carbon dosing and its impact on my SPS corals, specifically Acropora. I've been keeping SPS for many years, and my system is a 300-gallon SPS-dominated tank. Here are my parameters:

Salinity: 35ppm
Alkalinity: 9 DKH
Calcium: 450 ppm
Magnesium: 1400 ppm
Nitrate: 25 ppm
Phosphate: 0.06 ppm
pH: 8-8.2
Temperature: 78.5°F

As a background I consistently change my RODI filters and monitor alkalinity with an Alkatronic and a Trident, referencing a Hanna checker. I check other parameters with Hanna and Salifert kits and regularly recalibrate my pH probe. My system has a lot of flow (3 MP60s, 4 MP40s) and light (4 Orphek Atlantik V4s and OR3 bars). I maintain stability with a calcium reactor and kalk to boost pH, and I use a filter roller. I dose trace elements with the Captiv8 line and have just sent out an ICP test to double-check my levels. I don't run GFO or a reactor but use an algae scrubber and do weekly water changes with Reef Crystals to remove detritus.

Recently, I noticed my nitrate levels creeping up, starting at 15 ppm a couple of months ago and increasing by 1 ppm every few weeks. To get it under control, I began carbon dosing with vinegar, following the dosing chart and slowly ramping up over a couple of weeks. Despite reaching 100 ml per day, I saw no reduction in nitrate or phosphate. However, I did notice some of my previously happy SPS corals started peeling in the middle with their polyps out.

This is the second time I've experienced this with carbon dosing. (I am using vinegar) The first time, I thought it might be a coincidence, but now I'm convinced there's a correlation. I've stopped carbon dosing and noticed a bit of cyano on some frag plugs and dead tissue, which I never had before. I suspect that carbon dosing might be promoting the growth of bad bacteria, leading to STN or peeling in my SPS corals.

I know that carbon dosing works wonders for some reefers, likely because they don't have harmful bacteria strains present in their systems. For those who have success with carbon dosing, it can effectively reduce nitrates and phosphates by enhancing beneficial bacteria activity.

To address the issue, I'm now focusing on increasing positive bacteria strains in my tank by dosing beneficial bacteria to help outcompete the harmful bacteria. I'm hopeful this approach will stabilize my system and prevent further issues.

Has anyone else experienced similar issues with carbon dosing? I'd love to hear your thoughts.

Thanks!

Below was my sps a couple days ago. Great colours to what is now happening.

Sorry for your troubles. I had the same experience with ab+ amino acids. Twice it caused bjd outbreaks which i think is a bacteria imbalance.
Stopped all carbon dosing and amino acids. You are correct that they feed all bacteria, good and bad.
How do you know what bacteria to dose. What is good bacteria?

 

[Kruss7]

Sorry for your troubles. I had the same experience with ab+ amino acids. Twice it caused bjd outbreaks which i think is a bacteria imbalance.
Stopped all carbon dosing and amino acids. You are correct that they feed all bacteria, good and bad.
How do you know what bacteria to dose. What is good bacteria?

Completely agree. I am totally convinced that carbon dosing is harmful. My colours and polyp extension has gotten WAY better recently.

I don’t think bacteria dosing is all that important and think it’s a sales tactic to get people to continually dose, but I think if you’re having a bacterial problem that is the right time (or starting a tank)

I dosed Prodibio Biodigest and the AF line. I also did Rebiotic, Coral balance and Vib X.

Don’t know what worked but the STN stopped within a week after stopping the carbon and dosing the bacteria strains.

Would it have stopped anyways? I don’t know. But it stopped.

 

[Kruss7]

Here’s a pic of my Hw now that I stopped carbon dosing.