Biochurn. I bought the bio churn many years ago for biopellets. Its easy to refil and best imo for dialkng in pellets, gfo,etc. I use this reactor now for my gfo as i no longer use biopellets.
The BRS reactors have been the easiest for me.....I made the mistake of going with Bashsea reactors to match my sump. They are ridiculously hard to maintain.