Carbon dosing causes STN/RTN
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ReneReef
Active Member
Exactly my experience.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.
I’ve tried many different forms and products.
All with the same effect, tissue loss from the base of stony corals (even LPS in some cases).
There are very few things in this hobby I am certain about. But having witnessed this in so many instances and independent of the source, I am very sure that any carbon dosing in my tank is an absolute no go. Last year Oceamo SAC254 measurement showed to be high, even without carbon dosing.
In my tank, even the slightest dose of the supposedly mildest carbon source (e.g. bactobalance, reef activ) resulted in tissue loss. The effect was also very quick, within 24h a few mm of tissue loss would be visible on one or several corals. Also, I noticed an almost immediate effect on pH after dosing the tiniest amounts.
Why my tank is so sensitive, I don’t know. I did a biome test a few years ago. Nothing was out of the ordinary.
Over the last few years I started caring less about nitrate and phosphate levels. And focused on lighting and flow. I found out my corals looked just as beautiful with a nitrate 90 and phosphate of 0.5 as with values in generally advices ranges.
As a by catch I’ve also noticed that a lot of products contain quite large amounts of “carbon source”. For instance the carrier material in quim cyanocontrol is a carbon source. And TM Plus NP contains a carbon source as well (it is mentioned on the back of the bottle).
Lastly, we are not alone. I think our issue is more common than we think. I’m not saying carbon siding is bad. I know plenty of people that use is successfully and have beautiful acro tanks, my previous tank ran very successful with it as well.
But over the years I have had several friends come to me complaining about persistent STN issues. In all cases I recommended stopping carbon dosing or stopping a product that contains a “hidden” carbon source. In all cases STN stopped, corals recovered, nutrient levels increased with no ill effect.
Currently, my approach to reefing. Focus on the basics, good light, good flow, effective skimming, good pH. Maintenance: Balling with trace elements, water changes (biweekly to monthly), phosphate reduction with lanthanum and/or aluminium based absorber (no GFO), ammonium+urea dosing if nitrate trends down, a touch of ozone to keep the water clear.
After reading about the rather good outcome of the biome testing of the Aquaforest Fiji mud product, I’m now using that biweekly (in between water changes) to see if it can make my tank more resilient in time.
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My Tank Thread
I had the same experience.
Ozone caused issues for me to. It makes organics smaller and more bioavailable to bacteria.
I stopped carbon dosing for several weeks and then added a tiny dose of ozone for one day, and had the same STN effect.
Reef Rhino
Community Member
Kruss7:
To your point, I'd recommend Salem Clemens article on Reef Builders and some of his podcasts on D.O.C. and its effect on microbiome. A few Reef Builders videos and a recent appearance on Beyond the Reef (w/ Christoph Denk) talking about these issues.
Strongly suggests that we should focus on eliminating D.O.C., which may be feeding the bad bacteria (which can lead to STN/RTN). Questions why we would carbon dose, amino dose, or add bottled terrestrial bacteria strains not found in corals or reefs.
To your point, I'd recommend Salem Clemens article on Reef Builders and some of his podcasts on D.O.C. and its effect on microbiome. A few Reef Builders videos and a recent appearance on Beyond the Reef (w/ Christoph Denk) talking about these issues.
DOC is The Most Important Parameter For A Healthy Reef Tank: Here’s a New Method to Manage It | Reef Builders | The Reef and Saltwater Aquarium Blog
In this article, I will provide an overview of my take on the current zeitgeist of reefing and explain why the entire industry is ignoring a critical aspect of coral care. I will explain what issues…
reefbuilders.com
Strongly suggests that we should focus on eliminating D.O.C., which may be feeding the bad bacteria (which can lead to STN/RTN). Questions why we would carbon dose, amino dose, or add bottled terrestrial bacteria strains not found in corals or reefs.
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ReneReef
Active Member
There is actually a ton of science behind it, with real world data from actual reefs showing how increased dissolved organic carbon (DOC) leads to corals disease. Reef Rhino linked a summary of that.
To be clear: yes, carbon dosing = DOC dosing.
The science behind carbon dosing to lower nutrients comes from waste water treatment and commercial fish farming.
Do you aim to emulate a sewage treatment plant, a fish farm or a coral reef in your tank?
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ReneReef
Active Member
, I’m gonna follow up on this and see what turning off the ozone does.
When it comes to carbon dosing I consider two modes. Nutrient Reduction Mode, and steady state Maintenance Mode.
Whenever I increase carbon dosing with the goal of reducing nitrate, I find the phosphate level also drops. With my tanks, it takes about 0.100 ppm phosphate addition for each 1 ppm of nitrate reduction. Without phosphate addition the phosphate level will simply crash, leading to major problems including a freeze in nitrate reduction. It’s repeatable that my Acropora, LPS, and zoas do not like this mode, and they respond by browning and closing up. The root cause of this is unknown. Is it the nutrient instability, phosphate addition, bloom of irritating or undesirable bacteria, or the carbon itself? IDK. I cannot specifically recall if STN/RTN occurred during this time, but I would not be surprised if it did. For me Nutrient Reduction Mode is pretty hard on the coral.
After establishing a steady nitrate and phosphate level, and with reduced carbon and phosphate addition, my corals appear to be very happy. I think they appreciate the improved stability possible with managed carbon dosing. It can take a couple to a few months for the corals to adjust, but I have achieved better growth and color with carbon dosing than with other methods like a refugium or an algae turf scrubber.
But there is no question that my corals do not like the higher dose of carbon and phosphate addition of Nutrient Reduction Mode, that’s for sure.
Whenever I increase carbon dosing with the goal of reducing nitrate, I find the phosphate level also drops. With my tanks, it takes about 0.100 ppm phosphate addition for each 1 ppm of nitrate reduction. Without phosphate addition the phosphate level will simply crash, leading to major problems including a freeze in nitrate reduction. It’s repeatable that my Acropora, LPS, and zoas do not like this mode, and they respond by browning and closing up. The root cause of this is unknown. Is it the nutrient instability, phosphate addition, bloom of irritating or undesirable bacteria, or the carbon itself? IDK. I cannot specifically recall if STN/RTN occurred during this time, but I would not be surprised if it did. For me Nutrient Reduction Mode is pretty hard on the coral.
After establishing a steady nitrate and phosphate level, and with reduced carbon and phosphate addition, my corals appear to be very happy. I think they appreciate the improved stability possible with managed carbon dosing. It can take a couple to a few months for the corals to adjust, but I have achieved better growth and color with carbon dosing than with other methods like a refugium or an algae turf scrubber.
But there is no question that my corals do not like the higher dose of carbon and phosphate addition of Nutrient Reduction Mode, that’s for sure.
Pod_01
Valuable Member
That is interesting observation.
I have not observed a link between carbon dosing and STN/RTN yet…
I do carbon dose TM BB and TM reef actif (small amounts intended to feed bacteria so corals have alternative food source) but I do use GAC, makes me wonder if GAC removes some problematic DOC that leads to undesirable results!!!
I did have RTN/STN episodes over the years and the best I was able to do is link it to some trace elements overdose/ excess. Some was food related and some was following dosing recommendations by ICP companies… Just my observation…
Regardless I will have a look at the DOC once more…
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Kruss7:
To your point, I'd recommend Salem Clemens article on Reef Builders and some of his podcasts on D.O.C. and its effect on microbiome. A few Reef Builders videos and a recent appearance on Beyond the Reef (w/ Christoph Denk) talking about these issues.
DOC is The Most Important Parameter For A Healthy Reef Tank: Here’s a New Method to Manage It | Reef Builders | The Reef and Saltwater Aquarium Blog
In this article, I will provide an overview of my take on the current zeitgeist of reefing and explain why the entire industry is ignoring a critical aspect of coral care. I will explain what issues…reefbuilders.com
Strongly suggests that we should focus on eliminating D.O.C., which may be feeding the bad bacteria (which can lead to STN/RTN). Questions why we would carbon dose, amino dose, or add bottled terrestrial bacteria strains not found in corals or reefs.
If we think this is the way, how do we deal with allforreef, which is a form of carbon dosing?
ReneReef
Active Member
Plenty people. Including Hans Werner and Lou from Tropic Marin.
Well, I'm not touching it. But that is just my organic carbon trauma speaking. ;)
In the past (8 or 9 years ago) I have used ATI Essentials Pro, the alk in that is partially organic. I don't know if its formate (like in all for reef) or acetate. The effect on nitrate was huge, so if I had to guess I'd guess acetate.
The formate in all for reef is a very weak carbon source, much less than acetate.
Still, this also maybe why Tropic Marin put a max dose on the AFR label.
ReneReef
Active Member
I have used GAC (Rowa and others) in the past. If anything, using it seemed to exacerbate tissue loss.
With Lanthanum and aluminium based phosphate remover I do not see this effect.
Also, it has been shown that GAC removes much more besides just phosphate, including desired trace elements.
Lanthanum doesn't and aluminium based binders do it much less. So, that is another reason why I favour those.
Mixed up abbreviations starting with a G for granular... :face-with-spiral-eyes:
I have never overdosed a trace element, so I don't know which could plausibly cause TN.
I have seen what an fluoride over dose does in a friend's tank. That is very different from typical STN/RTN.
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Pod_01
Valuable Member
GAC - Granular activated carbon
I suspect you are thinking GFO - Granular ferric oxide that is used to remove Phosphate and will remove other things. I agree GFO is not easy to use and I had negative results from the use.
I generally let phosphate do its thing, I found over the years if I leave it tank does ok. Assuming there is at least 0.05ppm in the water.
ReneReef
Active Member
Oops
it's late in the evening here... :sleeping-face:About GAC, it seems not all GAC is created equal in terms of DOC absorbance. But no idea how much it matters.
Anyway, I did start using it again.
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Pod_01
Valuable Member
I used certain brand and ended up with elevated levels of Ba, some web search suggested GAC was potential source.Oops
About GAC, it seems not all GAC is created equal in terms of DOC absorbance. But no idea how much it matters.
Anyway, I did start using it again.
I switched to ROX 0.8 carbon based on Randy’s recommendation and no more odd ICP results.
As for DOC, it is doing something, water is clear and I only use skimmer and GAC.
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