starting bio-pellets: how should i build a good bacteria base?

[Lampshade]

I used this to get a good culture started. http://brightwellaquatics.com/products/microbacter7.php I used my old liverock that had a lot already though. As for pellets, most are made from the same thing, i have 2 different types in my reactor right now. I havn't played around or noticed a difference in different types yet.