Been using biopellets for about a year now. Definitely took awhile to get it dialed in, but now am happy with the results. Nitrates coming down, no extra bio snot.
You are going to get mixed results / myself tried pellets twice imo not easy to establish / switched over to a sulfur reactor / easier to adjust and no clouding of the water from overdosing / almost set it and for get it / also doesn't take as long to start working.