I have had great results with the bio pellets, great as in life changing for my tank. Total volume of the system is very important to consider, in my case I'm around 250 gallons. The more water volume the more nitrate reduction needed.
With my setup I actually purchased a reef octopus and put in 4 cups to start, this against many other suggestions to start around 1 cup but at the time my nitrates were out of hand to the point water changes were not going to significantly reduce the nitrates. It took right at 4 weeks to notice anything but after that point things reduced quickly. I ended up taking out half the bio pellets around the 3 month mark and dried them out when I got to 5 PPM Nitrate. I ended up leaving the 2 cups in so as not to rock the boat and have some head-room and ended up adding Nitrate if needed at that point. Over time the bio-pellets are consumed and I've found long-term the 1 cup level is a good happy medium given where I am now.
I also have my effluent from the reactor directed toward the skimmer and in this process at the 4 week mark the skimmer ended up with farm more skimmate than usual sort of all at once as a byproduct of the increased biologic activity.
So my take knowing what I know, you could try increasing the number of bio pellets as I believe you're past the point where they should have scaled up (4 week mark). Also make sure you have sufficient flow through the reactor, the beads should continue to churn relatively decently so that they bacteria attached to the pellets are knocked off by the churn.
