This is a very specific method of reducing nitrate and phosphate in a tank, and you need to be very well-read with this topic to do it successfully. There was a massive thread about it on RC, and I asked the main advocates to type up a full article on the topic. What you see linked above was five months of hard work to get that all into a recipe for success, but you need to follow it very closely. Please read it entirely at least twice before proceeding.
Once I had the article in my hand, I felt I had a good idea of what was going on and how to dose correctly. It took 8 months of daily dosing for me to see results in my own tank, but from that point forward it was amazing. I ended up dosing vodka for 2.5 years.
With my new tank, I decided I wanted to use biopellets which is easier. I ran a full year with zero nitrate and phosphate.
Vodka dosing isn't for the average hobbyist, and I wouldn't recommend it to new hobbyists.
O4-X which from what I read is pretty much a carbon supplement. My nitrates weren't bad, probably in the 5 - 10 ppm range but since I have gone mainly SPS I decided to try this stuff and it works well. in a week or so, my phosphates are measuring about .06 and nitrates under 1 with no bacteria blooms.