Make sure your reactor drains into or near your skimmer so it can pull all the crap out. Need to be sure all the pellets are moving as well. Dead spots in a biopelet reactor will create sulfur pits. I run only my biopellets and algea scrubbers and my nitrates stay at 0 and phosphates stay around .08-.1. And they're easy too. No replacing or changing media. Just add more pellets as they dissolve. They do last a while as long as you don't tumble them at warp speed
What problems are you tying to solve? They work ok to lower nitrate if you have some. If you don't have many nutrients, they can starve your coral. You will need a VERY good skimmer to pull out the bacteria that will grow.
I almost killed my entire sps tank with biopellets. I will never use biopellets again. You need to feed heavy if you want it to work right. I would do an algae scrubber over a biopellet reactor.