How to dose organic carbon.
Which organic carbon to use.
Other issues
. This section describes the types of organic carbon being used by aquarists and the techniques ,methods and rationales. It includes facts as well as summary statements of anecdotal experiences posted in the hundreds if not thousands of accounts that I've read over the last five years or so. It also includes my own and personal opinion and preferences. It is intended to be descriptive rather than prescriptive. Thus. it is hoped, enabling the reader to make informed decisions that fit his/her personal preferences .
Organic carbon used:
Type:
Polymers( carbohydrates) these include: bio pellets which are carbohydrate based plastics. There are different types but commercial hobby companies don't tell us what they are using so useful comparisons of pellet types beyond anecdotal accounts are unavailable. .BTW Some folks are using diy polymer plastics
Methods: reactor use, placement in canister filters or good flow areas in sumps are the most prevalent methods.
There are some products that contain tiny beads in liquid that some dose directly to the tank.
Comment and Opinion:
I was excited but skeptical about these when then first hit the market. Mostly because the were claimed to segregate bacterial activity and it's effects to the pellets without braodcasting the activity throughout the tank.
This proved untrue as there are many reports of cyano blooms, coral stress, and bacterial blooms ocurring with them indicative of off pellet activity, ie: monomers are diffusing, bacteria are growing off the pellets and bacterial by products are effecting some systems adversely in terms of cyano growth and coral health. I have not seen a report of long term success with them.There are now a myriad of bio pellet products and equipment to choose from for those who are so inclined.
They are expensive compared to other types.
Equipment is required for most applications adding to the cost and complexity of managing the dosing. In fact a majority of the posts on polymer pellets( aka bio pellets) concern reactor choices flow rates pellet amounts, etc. Disappointingly ,there is little focus on the bacteria culture which is the essence of it all.
It's hard to know or control how much organic carbon you are actually dosing at a given time. Pellets degrade, flow varies , clogs happen, etc.
They are polymers which I personally choose not to dose since a long cascade of bacterial activity some of which may be harmful by different strains occurs in degrading them down to acetate which is a beneficial substance to living things.
Sugar ( fructose, sucrose, glucose).
Polymers are degraded by the first wave of bacterial activity to monomers( sugars) . Sugar dosing has caused coral recession .browning.bleaching and death in a number of accounts and did so in my aquarium . The study noted earlier gives even credence to these anecdotal accounts. I personally have chosen to steer clear of monomers and the polymers that degrade to them. They do seem to work faster to reduce NO3 in the short run than acetic acid or ethanol ,though.
Vodka( ethanol and water):
is a step below monomers in the bacterial cascade known as acetogenesis. It comes from monomers. It does not go back to them but moves on via oxidation to acetic acid vinegar.
Vinegar:
, is acetic acid in water. The acetate is useful to living things. It's degradation is the last step in the cascade likely to occur in a reef tank.
These generic organic( vodka and vinegar ) carbons are:
inexpensive :
$3.50 per gallon plain whit vinegar which is 5% acetic acid
bottom shelf , plain charcoal filtered vodka @ $12.99 for 1.75 liters or 80 proof( ie 40% ethanol)
easy to dose: bolus dosing( ie. pour it into the sump or high flow area), additions to limewater or incrementally dosed via dosing pump;
Add only ethanol and acetic acid without monomers (sugars).
I've had over 3yrs of success in managing PO4 and NO3 and coral health with them.
Vitamin C( ascorbic acid)
is used by some for undefined perceived benefits . It is ,however , a carbon source derived from sugar with similar negative effects reported although the carbon itself may have some short term benefits.
Commercial products and other sources for organic carbon:
There are many forms and mixes. Some folks even advocated plain rice with disastrous results. Commercial mixes don't tell you what's in them. Knowing what I'm putting in the tank is important to me.
Other related issues:
Biodiversity: Some systems trumpet the use of a variety of carbon sources and bacterial supplements to ensure biodiversity in the bacterial populations . First of all, bacteria will be diverse, though some strains will dominate based on the type of food availalbe. For example , those that degrade polymers and monomers will be less in systems relying on ethanol and vinegar. More importantly, though biodiversity sounds good, there is no plausible reason to think it is has been articulated.If you could maintain it which is unlikely given that those using various carbon sources and bacterial supplements must continuously buy and dose the non viable bacteria,; it might easily be a bad thing as with sugars for example.
Supplementing bacteria:
A mostly useless practice and needless expense ,imo. Bacteria are ubiquitous and there are plenty in a reef tank ready and willing to consume organic carbon when it's added. They establish themselves and are viable. Introducing bacterial concoctions may interfere with a very natural and healthy process advisable cultures establish themselves in response to the food( organic carbon) offered.
Bacterial supplements are not useful in my opinion. There are plenty of viable indigenous bacteria in a reef tank that will pick up the task of consuming the organic C when N and P are also adequate.The bacteria in supplements are not viable in a tank. If they were there would be no reason to keep dosing them beyond intiial seeding other than to use more bottles of the concoction.
Complimentary practices:
There is no reason not to use other nutrient management methods with organic carbon dosing.
I run:
Chaeto refugia for some PO4 and NO3 reduction , opposite photo period oxygen and habitat for pods and such;
Cryptic rock filled refugia for surface area , habitat for pods and filter feeders such as sponges ;
A deep sand bed with rock on top.
GFO
GAC and excellent organics remover
Purigen
Skimmers: a must for the the aeration with carbon dosing in particular as well as the bacteria export.
Phosphate and nitrate imbalance:
The bacteria encourage by the organic carbon reduce nitrogen by taking some of it as food along with a proportionate amount of phosphate. However, they also deplete additional NO3 via anaerobic respiration wherein they take the O leaving some of the N to form N2 gas which bubbles out of the tank. This may lead to a situation where some extra low range PO4 is left which can be cleaned up with a little gfo or other remover.
How much to dose:
To iterate: if NO3 and PO4 levels in your aquarium are not an issue and other methods are working in your situation , then no dosing is needed.
The amount needed to maintain acceptable nutrient levels will vary from aquarium to aquarium as will imports, exports and other variables such as bioload, surface area, water change schedules, et alia.
Not all sources are of equal strength in terms of carbon content . The molecular structures are similar enough to generally equate them but if you want more precision checking teh formulas for a carbon source acan tell you precisely how many C atoms each contains. As a practical matter dilution should be accounted for . Thus vinegar which is 95% water is 8x weaker than 80 proof vodka which is 60 % water and 20x weaker than an anhydrous source like sugar or granular vitamin C. So if you are switching from vodka to vinegar for example , 8 mls of vinegar for each ml of vodka being replaced is the calculation. Likewise, 1 gram of sugar would be replaced by 20 ml of vinegar or 8 ml of vodka.
Finding the right dose for your aquarium is a matte of amping up slowly and monitoring NO3 and PO4 along the way.
I recommend reducing NO3 an PO4 before starting and then finding and implementing a maintenance dose.
Which organic carbon to use.
Other issues
. This section describes the types of organic carbon being used by aquarists and the techniques ,methods and rationales. It includes facts as well as summary statements of anecdotal experiences posted in the hundreds if not thousands of accounts that I've read over the last five years or so. It also includes my own and personal opinion and preferences. It is intended to be descriptive rather than prescriptive. Thus. it is hoped, enabling the reader to make informed decisions that fit his/her personal preferences .
Organic carbon used:
Type:
Polymers( carbohydrates) these include: bio pellets which are carbohydrate based plastics. There are different types but commercial hobby companies don't tell us what they are using so useful comparisons of pellet types beyond anecdotal accounts are unavailable. .BTW Some folks are using diy polymer plastics
Methods: reactor use, placement in canister filters or good flow areas in sumps are the most prevalent methods.
There are some products that contain tiny beads in liquid that some dose directly to the tank.
Comment and Opinion:
I was excited but skeptical about these when then first hit the market. Mostly because the were claimed to segregate bacterial activity and it's effects to the pellets without braodcasting the activity throughout the tank.
This proved untrue as there are many reports of cyano blooms, coral stress, and bacterial blooms ocurring with them indicative of off pellet activity, ie: monomers are diffusing, bacteria are growing off the pellets and bacterial by products are effecting some systems adversely in terms of cyano growth and coral health. I have not seen a report of long term success with them.There are now a myriad of bio pellet products and equipment to choose from for those who are so inclined.
They are expensive compared to other types.
Equipment is required for most applications adding to the cost and complexity of managing the dosing. In fact a majority of the posts on polymer pellets( aka bio pellets) concern reactor choices flow rates pellet amounts, etc. Disappointingly ,there is little focus on the bacteria culture which is the essence of it all.
It's hard to know or control how much organic carbon you are actually dosing at a given time. Pellets degrade, flow varies , clogs happen, etc.
They are polymers which I personally choose not to dose since a long cascade of bacterial activity some of which may be harmful by different strains occurs in degrading them down to acetate which is a beneficial substance to living things.
Sugar ( fructose, sucrose, glucose).
Polymers are degraded by the first wave of bacterial activity to monomers( sugars) . Sugar dosing has caused coral recession .browning.bleaching and death in a number of accounts and did so in my aquarium . The study noted earlier gives even credence to these anecdotal accounts. I personally have chosen to steer clear of monomers and the polymers that degrade to them. They do seem to work faster to reduce NO3 in the short run than acetic acid or ethanol ,though.
Vodka( ethanol and water):
is a step below monomers in the bacterial cascade known as acetogenesis. It comes from monomers. It does not go back to them but moves on via oxidation to acetic acid vinegar.
Vinegar:
, is acetic acid in water. The acetate is useful to living things. It's degradation is the last step in the cascade likely to occur in a reef tank.
These generic organic( vodka and vinegar ) carbons are:
inexpensive :
$3.50 per gallon plain whit vinegar which is 5% acetic acid
bottom shelf , plain charcoal filtered vodka @ $12.99 for 1.75 liters or 80 proof( ie 40% ethanol)
easy to dose: bolus dosing( ie. pour it into the sump or high flow area), additions to limewater or incrementally dosed via dosing pump;
Add only ethanol and acetic acid without monomers (sugars).
I've had over 3yrs of success in managing PO4 and NO3 and coral health with them.
Vitamin C( ascorbic acid)
is used by some for undefined perceived benefits . It is ,however , a carbon source derived from sugar with similar negative effects reported although the carbon itself may have some short term benefits.
Commercial products and other sources for organic carbon:
There are many forms and mixes. Some folks even advocated plain rice with disastrous results. Commercial mixes don't tell you what's in them. Knowing what I'm putting in the tank is important to me.
Other related issues:
Biodiversity: Some systems trumpet the use of a variety of carbon sources and bacterial supplements to ensure biodiversity in the bacterial populations . First of all, bacteria will be diverse, though some strains will dominate based on the type of food availalbe. For example , those that degrade polymers and monomers will be less in systems relying on ethanol and vinegar. More importantly, though biodiversity sounds good, there is no plausible reason to think it is has been articulated.If you could maintain it which is unlikely given that those using various carbon sources and bacterial supplements must continuously buy and dose the non viable bacteria,; it might easily be a bad thing as with sugars for example.
Supplementing bacteria:
A mostly useless practice and needless expense ,imo. Bacteria are ubiquitous and there are plenty in a reef tank ready and willing to consume organic carbon when it's added. They establish themselves and are viable. Introducing bacterial concoctions may interfere with a very natural and healthy process advisable cultures establish themselves in response to the food( organic carbon) offered.
Bacterial supplements are not useful in my opinion. There are plenty of viable indigenous bacteria in a reef tank that will pick up the task of consuming the organic C when N and P are also adequate.The bacteria in supplements are not viable in a tank. If they were there would be no reason to keep dosing them beyond intiial seeding other than to use more bottles of the concoction.
Complimentary practices:
There is no reason not to use other nutrient management methods with organic carbon dosing.
I run:
Chaeto refugia for some PO4 and NO3 reduction , opposite photo period oxygen and habitat for pods and such;
Cryptic rock filled refugia for surface area , habitat for pods and filter feeders such as sponges ;
A deep sand bed with rock on top.
GFO
GAC and excellent organics remover
Purigen
Skimmers: a must for the the aeration with carbon dosing in particular as well as the bacteria export.
Phosphate and nitrate imbalance:
The bacteria encourage by the organic carbon reduce nitrogen by taking some of it as food along with a proportionate amount of phosphate. However, they also deplete additional NO3 via anaerobic respiration wherein they take the O leaving some of the N to form N2 gas which bubbles out of the tank. This may lead to a situation where some extra low range PO4 is left which can be cleaned up with a little gfo or other remover.
How much to dose:
To iterate: if NO3 and PO4 levels in your aquarium are not an issue and other methods are working in your situation , then no dosing is needed.
The amount needed to maintain acceptable nutrient levels will vary from aquarium to aquarium as will imports, exports and other variables such as bioload, surface area, water change schedules, et alia.
Not all sources are of equal strength in terms of carbon content . The molecular structures are similar enough to generally equate them but if you want more precision checking teh formulas for a carbon source acan tell you precisely how many C atoms each contains. As a practical matter dilution should be accounted for . Thus vinegar which is 95% water is 8x weaker than 80 proof vodka which is 60 % water and 20x weaker than an anhydrous source like sugar or granular vitamin C. So if you are switching from vodka to vinegar for example , 8 mls of vinegar for each ml of vodka being replaced is the calculation. Likewise, 1 gram of sugar would be replaced by 20 ml of vinegar or 8 ml of vodka.
Finding the right dose for your aquarium is a matte of amping up slowly and monitoring NO3 and PO4 along the way.
I recommend reducing NO3 an PO4 before starting and then finding and implementing a maintenance dose.
