To reiterate further, vodka being 90 proof (40 percent APV) contains less than half the alcohol (carbon) per volume of liquid ...
40% ABV would be 80 proof.
I understand the remaining content is "mostly" (how accurate is mostly, exactly ... disc1 ?) distilled water, but it's my nature I prefer the aforementioned highest percentage of the actual catalyst (alcohol/carbon/etc) in question, per volume stat, when adding a chemical/liquid within my reef system.
I would greatly appreciate as much information, an elaborate/in depth breakdown would be great!, as you can think of ... Comparing/contrasting Everclear brand grain alcohol, as a bacterioplankton carbon source, versus regular old distilled vodka ... Thanks in advance : )
So think about how vodka is typically made. They double or triple distill alcohol to a very high proof and then add water to bring it to a drinkable level. So in the end, you're not really getting anything different.
That said, there's no harm in buying 190 proof grain alcohol and using that. The amount you dose will be less, and depending on the size of your tank that may necessitate diluting the alcohol to get an amount you can measure easily.
The only caveat would be price. There is a reason so many liquors are 80 proof and no more. In many states there is an extra tax for liquor that is more than 40% or 50%, so grain alcohol may cost more for the same amount of alcohol depending on where you live. In other places the grain alcohol may be cheaper. You'll have to do your own comparison.
Are there other substances present? Sure, there will be trace amounts of sugar or other things, but the amounts will be so very very tiny that they can be ignored. You'd get more fructose in your tank if you ate an apple with your bare hands, washed them, and then stuck them in your tank.
So to get at the last question, comparing the two: Aside from price and the actual amount dosed there is no difference.
What you want to stay away from is anything that is intended for the lab or the chemical industry. There is always extra tax if it is drinkable, so it will almost always be denatured. I've had to buy non-denatured alcohol for the lab and do you know what we did? We went to the liquor store and got Everclear because the chemical supply companies pass that tax on to you and then some. There's a real big price difference to get the non-denatured stuff. And I'd stay away from the denatured alcohol unless you know exactly what you're getting and exactly how to tell.
