My Tank Info
Vodka Dosing: My Experience to Decrease Nitrates and Phosphates
This is my site Written by GeoffM1968 on December 19, 2008 – 10:40 pm

Probably like most newbies, I have been watching my nitrates and phosphates creep up and watching Acropora suffer from increased nutrients. To successful raise SPS corals, I need to have a low nutrient system so I needed to find a way to export these nutrients. Looking for a solution, I found people having success with Vodka dosing.

The Plan

The theory behind Vodka dosing and other carbon based dosing systems is to create a source of food for beneficial bacteria which will feed on the nutrients you want to export from your system. Vodka is one of the most pure form of ethanol which in theory is great source of food for these beneficial bacteria.

Like any new dosing regime, you want to start slow, watch your inhabitants, and adjust. You want to start at 0.5 ml/day and increase every week 0.5 ml/day until you observe your Nitrates and Phosphates begin to drop. In other people’s experiments, this is where you are suppose to cut the dosage you reached in half. This is now your maintenance dosage which should be no more than 1.0 ml/day for my 25 gallon reef tank based on other people’s experiences. Again, can not stress enough, you want to go slow as you need to grow your bacteria population. Any sudden increase will have negative impacts on your inhabitants as their are no bacteria colonies to consume the ethanol.

While trying to determine your maintenance dosage, watch your tank for any negative impacts to your inhabitants or a sudden bacterial bloom. If observed either, you will want to discontinue for a few days, access your results, and resume.

Another part of the Vodka Dosing system you need is a great skimmer. You want a way to export the waste from the bacteria consuming your nutrients. You will notice your skim turning from the green skim to a black crud. This is expected.

With these in place, you will want to ensure you are measuring and tracking Nitrates and Phosphates to observe the decrease in their numbers. With luck, this system should help you create a low nutrient system which you can maintain over time and then positively impact the health of your inhabitants.

The Goal

  • Nitrates below 4.4 ppm using LaMotte Test Kit
  • Phosphates below 1.0 ppm using Low Phosphate Hanna Meter
  • Maintenance dosage should be 1.0 ml/day
  • Improved SPS Coral Health
  • No negative impacts on system

Observations and Information

  • 12/19/2008 — Starting dosing Vodka at 0.5 ml/day (Nitrates 10 ppm, Phosphates 1.0 ppm using Salifert test kits)
  • 12/25/2008 — Increased Vodka dosage to 1.0 ml/day (Nitrates 10 ppm, Phosphates 0.0 ppm)
  • 01/01/2009 — Increased Vodka dosage to 1.5 ml/day
  • 01/06/2009 — Switched to LaMotte Nitrate Test Kit as allegedly most accurate kit available to consumer as science grade
  • 01/06/2009 — Increased Vodka dosage to 2.0 ml/day (Nitrates 8.8 ppm, Phosphates 0.0 ppm)
  • 01/18/2009 — Increased Vodka dosage to 2.5 ml/day
  • 01/22/2009 — Increased Vodka dosage to 3.0 ml/day (Nitrates 4.4 ppm, Phosphates 0.0 ppm)
  • 01/28/2009 — Increased Vodka dosage to 3.5 ml/day (Nitrates 1.1 ppm, Phosphates 0.0 ppm)
  • 02/07/2009 — Increased Vodka dosage to 4.0 ml/day (Nitrates 0.0 ppm, Phosphates 0.0 ppm)
  • 02/07/2009 — Determined maintenance dosage to be 2.0 ml/day based on achieved results
  • 02/11/2009 — Began using Hanna Meter Low Phosphate as most accurate testing equipment for the consumer
  • 02/22/2009 — Observed increase in Nitrates and Phosphates (Nitrates 8.8 ppm, Phosphates 0.04 ppm)
  • 02/22/2009 — Increase dosage back to 4.0 ml/day as feel recent enough to have minimal negative impact
  • 03/01/2009 — Increased Vodka dosage to 4.5 ml/day (Nitrates 4.4 ppm, Phosphates 0.07 ppm)
  • 03/06/2009 — Increased Vodka dosage to 5.0 ml/day (Nitrates 2.2 ppm, Phosphates 0.04 ppm)
  • 03/14/2009 — Observed increase in Nitrates and do not want to increase vodka dosing as I feel I am at a too high of safe dosage. Corals still look healthy but notice a change in the deep sand bed color to dark brown about inch below surface of sand. Allegedly this is sulfur which is a by-product of some anaerobic bacteria (Nitrates 8.8 ppm, Phosphates 0.02 ppm)
  • 03/21/2009 — Observed another increase in Nitrates. Not sure why seeing increase but from observations of sand bed, I assume I may not have a colony of beneficial bacteria I need. Corals still look healthy except for my Hammer Coral (Nitrates 17.6 ppm, Phosphates 0.02 ppm)
  • 04/04/2009 — Observed increase in Phosphates. Still can not determine why not seeing good results in the nutrient numbers (Nitrates 17.6 ppm, Phosphates 0.04 ppm)
  • 04/12/2009 — Cut dosage to 2.0 ml/day to observe any changes and restart Vodka dosing process as feel 5.0 ml/day way to high based on what I have read (Nitrates 17.6 ppm, Phosphates 0.05 ppm)
  • 04/17/2009 — Increase in both Nitrates and Phosphates which is to be expected if I did not determine new maintenance dose as stopped at 5.0 ml/day (Nitrates 26.4 ppm, Phosphates 0.09 ppm)
  • 04/17/2009 — Disappointed by results as Nitrates and Phosphates are creeping up, discontinuing dosing and starting experiment with ZEOvit System. I want to blame either my deep sand bed or not growing the type of beneficial bacteria I needed. Like what I have read and heard about ZEOvit System
  • 4/18 — Starting to reverse dosing process by reducing dosage per day by 0.5 ml every week
  • 5/08 — Stopped Vodka dosing today


Initially, I saw great results with both Nitrates and Phosphates reducing to undetectable levels when reached 4.0 ml/day dosage. At this point, cut dosage in half to what was suppose to be maintenance dosage of 2.0 ml/day. Right after, observed Nitrates and Phosphates to start to increase so went back to find new maintenance dosage. Once reaching 5.0 ml/day, I stopped as everything I read said I should not need to be dosing at that level as my daily maintenance dose should be 1.0 ml/day for my 25 gallon tank and with this number, my maintenance dose would be 2.5 ml/day or higher.

Maybe I stopped to early and what I have read is incorrect for my system. But with this information, observations of my deep sand bed, information others who have failed who also had deep sand beds, and recommendation from my LFS to try ZEOvit, I decided to end the Vodka dosing. As I switch to ZEOvit, I will continue to slowly decrease the daily dosage by 0.5 ml/day each week until completely discontinued.

DISCLAIMER: Your results may very as each system is very different from another. For my tank parameters and environment, this was my observations and conclusion. This was not a controlled experiment so there is a very large margin of error. I would like to see some good scientific experiments on the subject as I would be willing to give it a try again.


Walton , Nathaniel A., and Bjornson, Matt. “Vodka Dosing…Distilled!” Reefkeeping Magazine. Aug. 2008. http://reefkeeping.com/issues/2008-08/nftt/index.php. Accessed 19 December 2008.

Modified: November 26, 2009 at 11:01 am UTC