I am using bio-pellets for over a month now and don't have any problems. Never used vodka but you should do a lot of research before you use either. Key to using bio-pellets is to use very small amounts and slowly build up. In most cases if you use too much then you would get a cloudy tank or have a huge algae bloom and have to just wait it out. I use TLF 150 reactor with a MJ1200. Just removed the sponge filter and use a mesh that you get at a hobby store. BRS has a new reactor that is very affordable and actually tumbles the pellets in a vortex motion and comes with a pump. If you search reef central there is a thread that had and experiment done comparing vodka dosing, bio-pellets, gfo and something else.