Do you know if the benefits from the vodka come from just the ethanol component or if the additives are important too? The reason I'm asking is if it is just the ethanol, then we could buy dilute lab grade ethanol and mix it with the water in your ATO.
I found that dosing through the ATO was a mistake because the dosing volume changed wildly from summer to winter, same reason why I don't use it for kalk anymore. Also, diluting the ethanol to a really low percentage might allow it to "spoil". I never tested I would think anything lower the 12-15 percent would allow it to break down.
I broke down the 120G tank that had setup and was dosing. But here is what I remember....
I believe that that the ethanol is the active food source for the bacteria. Diluting the ethanol down with RO/DI water works great. When I was Vodka dosing (well started with Vodka then switched to Everclear) that was diluted, I used the same solution for dosing and for sanitizing my yeast culturing containers (yeah, ex-hombrewer). However, I have the pleasure of living in a dry county, and it was a pain to drive across the mountain to get supplies. So I switched to vinegar dosing and it worked great, it's just another form of carbon. Also, it's available just about anywhere so.... no more driving 50 miles round trip to get stuff. The only caveat is that ethanol has more carbon (something like 8 times, I think) then vinegar, so vinegar is easier to dose accurately.
After awhile, I got board and thought I could tweak the system and make it better.I accidentally something that many reefers had known for long time adding lime (aka kalk) with vinegar works better! I believe the chemistry of it is lime plus vinegar equals acetate, there is a big long thread of it here somewhere.
Great article on "Carbon dosing"
http://www.advancedaquarist.com/2011/3/aafeature">http://www.advancedaquarist.com/2011/3/aafeature</a>
Vinegar Dosing
[IMG]http://reefkeeping.com/joomla/index.php/current-issue/article/116-vinegar-dosing-methodology-for-the-marine-aquarium">http://reefkeeping.com/joomla/index.php/current-issue/article/116-vinegar-dosing-methodology-for-the-marine-aquarium</a>
Short story made really long.... without a doubt I would use carbon dosing again (and will do it in the upgrade) for nutrient control.