There are a number of different ways to address exporting issues. I'm not advocating how I export is the only way or for anyone else to copy it. But this works for me, as my tanks shots show. I'm simply looking for a way to improve and make reef keeping easier. I call it NPR....no realtionship to National Public Radio
It is my Nitrogen/Phosphate Ranching (NPR) system to grow and export nutrient rich bacteria........
As with any additive Vodka dosing can be easily misapplied and be a disaster, as has been described in some responses. I can also show you similar failures with every method for exporting or biologically treating waste in reef keeping; be it DSB, BB, Plenums, Fuges, Zeo, Phos removal medias,etc. It does not mean they don't work. For every failure I can show you someone that has succeeded.
I have read dozens of accounts of success and failure in using Vodka, with conventional tank addition methods. Most of the failures were because a user applied ten times too much, had no idea of how much to dose, and/or had no idea of what to look for as indicators to increase, reduce or stop dosing.
Nitrates are easy to export, but phosphate will slowy build and cause problems, since they get deposited in substrate and in the live rock.
I don't add Vodka to simply increase bacteria production. I use Vodka to build bacteria biomass in a manner that allows me to concentrate the biomass to make it easier export nitrates and phosphates on demand. Simply coating everything in the tank with a layer of bacteria can be dangerous. If biomass on the rocks and substrate does not get into the water column so it can be skimmed, it is simply redeposit into the tank as the bacteria dies. My method reduces the risk of phosphates being dissolved back into the system as the bacteria dies.
I've been doing this for nearly a year. It works. The short version....
At the top of my recirculation tank I built a 3" deep rectangular tray with two large holes on the bottom. Two coarse nylon bag filter set in these holes. Into the bags I add a handful of filter floss. All of my tank overflow is directed through the bag filters. As the bag filter begin to clog with waste, the water rises a couple of inches and over flows the tray into the recirculation tank.
My tank has periodic heavy recirculation and little waste ever collects on the bottom. The floss always has detrius and uneated food in it, so I always have nitrogen and phosphate available in the filter to limit the possiblity of the bacteria growth becoming N or P limited. If I am not using it in conjunction with Vodka dozing the bags and floss are emptied daily so they do not become a nitrate factory. It is a two minute job....10 minutes in the morning with a cup of coffee.
Before I go to bed, I only dose 1/2 ml of Vodka / 25 G of tank capacity but it is directly into the filter tray...not into the tank. I also dose an amino acid and dry phytoplankton mix with the Vodka to enrich the bacteria. Within two hours you can see the bags develop bacteria slime on the outside.
If my tank has excess nutrients, the floss inside the bag filter will clog and cause the water flowing into the tray to start over flowing within 6 to 8 hours. The outside of the bag looks like Santa's beard from the bacteria slime. When I am dosing Vodka I do not let the bags go more than 12 hours without being emptied, otherwise the bacteria slime starts breaking down and reentering the water column.
The over flow indicates to me the bag is loaded with a nitrogen and phosphate laden bacteria biomass. In the morning I toss the floss in the garbage....the most positive export I can think of. The floss is like picking up a hand full of snot or watery jello it is so filled with bacteria. My skimmer is working over time while I'm dosing Vodka.
If the tray doesn't over flow within 8 hours from the build up of biomass, I stop dosing Vodka for a week, and then start over again. The reduced bacteria grwoth indicates to me P and N are reduced enough. It maintains enough nutrients to keep softies and reduces them enough to keep SPS. The mandrin, tangs, etc; are all fat.
While I am dosing Vodka I don't feed the tank. Although bacteria build up in ther tank is reduced, if you look closely you can see that there is plenty of white bacteria film on all the surfaces and in the water column for the fish and coral to feed on. The fish love the white bacteria film and nibble on it all day.
Neither excess nitrates or phosphates, nor available coral food are an issue in my system. The tank is bare bottom. I can start and stop the system with out adverse effects. As I said, it works for me. I am not worried about my tank suddenly flipping from uncontrolled phosphate release, if for any reason pH or salinity changes.