Well here's my update on Biopellets. I'm abandoning right before leaving on a long trip (3 weeks). I followed instructions, built up amount slowly and all the way to the final level, but I got a bacterial bloom (cloudy) that only stopped when I took the biopellets offline. I washed the pellets, threw away 3/4 of them, waited for the tank water to totally clear, and restarted. Bacterial bloom started again.
I have an established tank and a lot of other nitrate reduction stuff going on (algae scrubber, sulfur reactor), so not sure if I have a controlled experiment to report. The problem may have been with the ghetto DIY reactor I built, who knows. Anyway I guess the moral is, from my run with them, you have to be careful and take it slow. You may just ween off the vodka and see if your tank really needs carbon first? Before you start biopellets?
Also, I would not throw them online right before you leave. You should run it for at least a few weeks while you can watch for signs of the bad effects.
My $.02