The use of Carbon as a filter medium against the NO2 / NO3 and PO4 load in our seawater aquariums is absolutely nothing new, every engaged reefer knows this.
Since many years ago, still as of today they use various carbon sources for the NO2 / NO3 and PO4 reduction. Whether they use now sugar, honey, methanol, cotton wadding or just also vodka (to call the most important ones), all precalled ones are more or less well suitably to be held the NO2/3 as well as PO4 load in our mostly over manned aquariums in defensible borders. Only the kind of use and the possibility of an exact dosage of the precalled sources make a distinction in her usability. The only one of the precalled carbon sources with always the same ones carbon content, by the alcoholic content given ones, is vodka. In sugar and honey as well as the cotton wadding rather different amounts of carbon are included, they can be measured therefore only hardly precisely. A very precise dosage is in my eyes decisively for a successful application this „filter media“ in the aquarium.
In many articles and various forum - and professional-contributions all around the globe, it is written that vodka is standard use as filter medium. I would like to emphasize the contributions of Michael Mrutzek and Jörg Kokott on the subject Vodka method, two engaged German Reefer and LFS Owner. They have reported in detail and specifies above the way walked by them in different professional articles and talks as well as forum contributions. The resonance on all these contributions and articles reached from 100% approval up to strict refusal. One finds more strangely wise under those aquarists they reject the vodka as filter medium in general, most aquarists who never used vodka, but him for badly or even dangerously have classified. What's all this about? Certainly you can reject, a filter method because it does not count as a „ natural method “, to classify them in general as bad or even dangerous without having collected ever own experiences with it is in my eyes more than only exaggerated, not to say questionably.
First I read or heard some years ago in the USA about the use of vodka or Ethanol as „filtering medium „ and as a result I decided to try it. Although the application of vodka/ethanol even then in the USA, and I know now also here in Germany, way more than controversially discussed, I am decided on the application. Because it was also reported about misses, even if rather seldom, a very careful and rather slow approach was right. The amounts given at that time for 100 gallons aquarium water seemed to me to high. Because I did not know it better, I decided to begin the first attempt with a 99 Gallon Tank (375 liters). The aquarium was well taken with various soft corals and anemones as well as anemone fish, a pair gobies and various higher algae. The construction existed of base rock and „live rock“ from the Pacific (Tonga; Fiji etc.). The aquarium was already about more than a year in use, however had to fight constantly with nitrate values around 20 ppt.! The aquarium was running as a „Berlin System“ with a strong Skimmer, three current pumps (4500 gal/h) and (40gal) sump. I used none filter sponges or even Bioballs.
I bought a bottle of vodka and 5 ml as well as 1 ml disposable syringe to the better and very precise dosage and began with 1ml Vodka on converted 100 liters of aquarium water. The first dosage was 3.75ml vodka, 3ml from 5ml syringe and 0.75 from 1ml syringe. Better a little bit too carefully, as well as only a little too carelessly, was my motto.  The nitrate value was approx. 20 ppt as described already before, Nitrite was not provable and PO4 I measured with approx. 0.2 ppt.
After 7 days no change was noticeable in the nitrate and PO4 values and I raised the dosage by 1ml on a total of 5 ml for the next 7 days. Now some changes were to be observed.  I had to empty the skimmer cup during some days twice. The contents of the skimmer cup were clearly bright and the foam itself existed of substantially bigger bubbles. At the end of the second week, I could ascertain a slow sink of the nitrate value, however the PO4 remained unchanged. The animals, corals as well as the anemones and fishes, are seemed to feel very well. I could ascertain, in any case, no change too the week before.
I started the third week with another increase of the dosage around 1ml on a total of 6ml vodka now and decided to measure the values from now on also at least 2 times per day. By the mid of the third week the nitrate value sank continuously further on approx. 15ppt. In the panes of the aquarium as well as the superstructures a thin white-grey bacterial layer formed, very clearly recognized on the usually black pump case. At the end of the week the nitrate value on approx. 10ppt had sunk and I note first „move “ on the PO4, it had sunk in the meantime clearly under 0.1ppt.
I began the fourth week with another rise of the dosage on now a total of 7ml vodka and was tensely what probably this week would act. I hoped it would further go down with the nitrate and PO4 values, but „Fiddlesticks“…. no such thing, not a bit of it. Now bacteria threads formed in the aquarium, I thought at least this were bacteria threads (today I am sure). It was at first only a few I simply with a tube sucked off. I had to empty the skimmer cup now regularly twice per day. At the end of the fourth week no other change was to be seen and I raised the dosage on 8ml vodka and start the fifth week.
In process of the fifth week I could ascertain the strongest changes. The white layers on the superstructures and the glass became more and more visible. I cleaned the pane up to twice per day. The corals seemed to manage the bacterial layer rather well, I could ascertain at least no signs from „ indisposition, likewise to the fish. The nitrate value sank on a value from under 5ppt and PO4 had likewise sunk with a value by approx. 0.03ppt.
My purpose to reduce nitrate to a value from 1 to 5 got closer and I started the sixth week with another rise of the vodka dosage on now 9ml daily. Slowly it became dramatic. The nitrate value sank within the first three days in the sixth week on roughly ZERO, PO4 was with approx. 0.01ppt, my purpose was therefore „ almost achieved “. However, the bacterial layers and threads became more and more and I decided to reduce the dosage at first around the half. The right decision as later should turn out. Within only 3 days the white layers disappeared almost completely. Also the bacterial threads disappeared on „never see again “.  The water was crystal clear at once, merely on the pumps and the panes a however very thin film formed which I still remove daily. Now the dosage was everyday only 4ml. The strains of bacteria had to be nourished to be able to do her effect. I hoped the values would not rise again and my hope was heard. The nitrate value settled down during the coming days between 1-5 ppt, the PO4 between 0.01 and 0.03ppt.  It could not be better, hopefully also during the next weeks without to have to increase the dosage?
I further measured only 4ml every day, the values did not change any more seriously, only marginal changes were to be measured. They swayed easily like already before described. NO3 between 1 - 5ppt and PO4 between 0.01 - 0.03ppt. Nitrite, ammonium or even ammonia was not provable.
After several months of the successful application I reduced the Dosage even to only 3ml vodka daily, the nitrate value further fell and at times any more was provable.
In the meantime, it is another aquarium where I apply the vodka method; however the size (volume) is roughly the same.  Now I have several other aquariums, with the same approach, on the already before called low values brought, I liked to call this method easily and save applicable. With a lasting dosage of only few milliliters of vodka daily disappeared in general in all aquariums after „leveling“ of the values and the reduction of the dosage on the absolute minimum, after few days also the last white layers on panes and superstructures. The values stabilized in nearly all aquariums permanently.
The application of the vodka method has a pleasant side effect in addition to lasting and reasonable lowering the nitrate and load PO4. Phosphate absorber is not required any more whose job takes over the vodka with what saves some € Euro ($) in the year in maintenance for my various aquariums to me.
For my present reef aquarium I use 3ml vodka daily, at the pure fish aquarium I am use 8ml daily and the values are already absolutely stable since many months, partially even for many years
For bigger aquariums one needs of course also a larger amount of vodka, however, my 1,000 liters aquarium gets by, in the meantime, also with an everyday dosage of only 7 ml vodka. The values are also consistently stable here, like in all other aquariums, for months. A very careful increase and immediate reduction around approx. 50 % of the dosage by a too strong development of the bacterial layers is very important. If you handle the dosage as described, it does not arrive mostly.  Also one can increase completely easily after 50% of lowering of the dosage slowly again if inevitably.  As already said, you must go forward in small steps and with a lot of patience, then this method is absolutely successful and applicable without any loss.
Heinz Mahler © July 2008
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