Dosing Sugar or Vodka

I am going to quote Eric Borneman on this subject simply because his summarys are brief and to the point. This pretty much sums up a great many things we, as hobbyists are either guilty of, or have been persuaded to try.
Quote " You gotta love aquarists and their perpetual need to add things to tanks. What are people doing that they have such problems growing corals? My hunch is doing things like adding vodka, mud, sugar, majick products, and other things same as they have been since I have been in the hobby. Is it because they have tank issues, because they purposely want to play scientist in some non-scientific way like a tank is a big test tube, or is it the lure of finding something and then marketing it and making their way to fortune and glory? " Unquote.

The theory behind adding sugar or vodka to our aquariums as touted in a great many discussions online goes something like this. There are denitrifying bacteria living within our sand beds, being a bacteria, they use carbon sources as an energy source to do their conversions of nitrates to nitrogen gas. By feeding the aquarium a carbon source such as sugar or vodka, the resultant bacterial bloom kicks the denitrification process into high gear and the nitrates are gobbled up in short order. Which can happen. Sounds great, right? Well, as usual with such methods, those that promote it do so based on only achieving the desired results with no thought given as to other possible consequences. All of which goes back to my rant about learning to be a lot more critical in our thinking.
So what possible consequences could there be? Simply, the bacteria themselves. Since there are a great many bacterial strains within our aquariums at any given time, any addition of carbon sources are going to be of benefit to all bacterial strains. Not just the desirable denitrifying strains. This is what all the proponents of this method fail to mention or consider.
A clue to this being a problem can be found in the study of fish bacterial diseases. Since there can be, and usually is, a great many strains of bacteria in our aquariums, at normal day to day levels, the fishes own immune system is capable of keeping the bacteria at bay. When an overload of nutrients drives the bacterial count up, the fish are unable to ward them off anymore and they can become overwhelmed and infected. The bacterial "pop eye" disease is a good example. Look up the treatment plan for this disease and you will find it recommended to do large water changes and get your nutrient controls in place, when done, the fish, due to the reduced bacterial presence will recover on its own.
This very same result is a very real danger to corals as well. Adding a carbon source (sugar or vodka) to your reef aquarium's water will drive up ALL bacterial counts, which while some strains are busy at denitrifying your water, other strains will be busy trying to infect your livestock. While a healthy coral or fish may be able to ward off initial large scale attacks, and is probably the reason some will claim having obtained great results with this method with no "damage" done. All they achieved was dodging a bullet, this time. Keep on adding sugar or vodka, and sooner or later, a coral or fish is not going to be at its optimal health and become infected and possibly die. Just the act of dosing such substances could very well cause the fish or coral to become more susceptible to this method over time. Having to expend energy and the stresses placed upon its immune system, will sooner or later catch up with it.
Please, Do not be tempted by fads, "new" methods and just plain bad science in an attempt to somehow get around the basics of aquarium reef keeping. Water changes, proper feeding, lighting and stocking levels will take you much farther with a great less risk.

Being a reef tank, with Corals as the (my) only concern. It is the balance of the system, just as is required on the reefs the Corals evolved on, that is imperitive. Although, in a fish only system, elevated bacterial counts also pose a threat to fish. If elevated carbon levels only effected the bacteria that are deep down in a sandbed, then there is no issue. But taking into account that all bacteria are driven by carbon sources, then ALL bacteria have to be taken into account and not just those that we intend the sugar for. Again, I think its simply just a matter of balance.
Every aquarium is going to be different in the amounts of sugars produced and utilized. Some aquariums are so good at nutrient control, very little sugar is produced (by algae). When sugar is added, such a system most likely has plenty of "room" for a bit extra sugar with no ill effects, other aquariums are not so good at nutrient control, and may have quite a bit of sugar (by algae) already available. When sugar is added, such a system does not have the extra "room" and its sugar levels quickly reach the point to where the coral's bacteria turn deadly on them. This (to me) sounds like a logical explanation as to why some tanks seem to "do good" and some tanks "crash and burn" when the same amount of sugar is dosed.
Which then you have to ask - What is my tank's sugar load normally?How much sugar can I add and get away with it?
Since youcan not test to answer those questions, then it becomes simply a question of "Am I willing to take a chance on an unknown and HOPE I get away with it?"
The above also negates any responses of "do an experiment to further the hobby" simply because each and every tank would be greatly different and your one teaspoon per week/month that does so well for you, could very well kill ten other tanks, and it all comes down to (for good reason), the basic tenant of reef keeping: " Thou shalt not add if thou can not test "

Need the Proof? Then please read further -

Sugars and Bacterial growth kills off Corals - " The research shows that sugars, or dissolved organic carbon, trigger an overgrowth of normally coral-friendly bacteria that in turn overgrow and kill off the coral. Studies have shown that bacteria are present in corals and contribute to their survival. The role bacteria play is just barely starting to be understood.

Sand beds and Vodka - This article is a must read, in my opinion. Please take the time to do so.

Sand beds and Vodka Part Two

References : Neilan M. Kuntz, David I. Kline, Stuart A. Sandin, Forest Rohwer. 2005. Pathologies and mortality rates caused by organic carbon and nutrient stressors in three Caribbean coral species. MEPS 294:173-80

Kline, D.I., Kuntz, N.M., Breitbart, M., Knowlton, N., and Rohwer, F. Role of elevated organic carbon levels and microbial activity in coral mortality. Marine Ecology Progress Series 314: 119-125, 2006

Ritchie KB, Smith GW (1995) Preferential carbon utilization by surface bacterial communities from water mass, normal, and white-band diseased Acropora cervicornis. Mol Mar Biol Biotech 4:345–354

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