I think that 1ml per 20 gallons is about the end result of the folks using vodka. That is about my limit. I would encourage you to read the thread discussed by Randy and Mark. I also forgot about Marks large algae bloom discussed in the thread. I believe his result was the same as mine. It didn't hurt anything, but was a concern in terms of oxygen levels.
I also agree with Randy that low nutrient levels could become a limiting problem for desireable elements of our tanks such as corals. This has not been my experience as my corals have always been fine in terms of apparent health and growth. I would add that I house about 20 fish in the system and feed heavily. That was one of my incentives to start using vodka.
I should add, however, that, my tank is only sps, a few acans and clams. I do not house soft corals. I have seen way more concerns about lowered nutrient levels and using alternative food sources in soft coral tanks.
Lastly, you are trying something that is experimental. In fact, a lot of what we do in our tanks is experimental even when touted as absolute. The fact is no two tanks are the same, ever. There is so much biology and diversity in our systems that when you add varied husbandry routines you can never say that what happens in one person system will work exactly the same in another persons tank. This doesn't get stated enough in forums such as Reef Central. Instead, we just argue over absolutes that can never be proven.
. Also I would like to point out that I also used to use vinegar with my kalk and never had any problems. I dosed the vineger per Randy's recommendations. Towards the end of my kalk dripping days (before my big mishap with over dosing), my tank was doing great. I hope to get back to that soon.
