Think of bacteria populations on OC as turning a cruise ship... takes a while... and might take even longer if you abort one turn and start another.
I have never used bio pellets. A friend told me that he quit because he did not see anything get exported from the tank - like extra skimmer output that you get from dosing V/S/V. If this is true and all that you are doing is growing things that stay in the tank and hold on to the extra building blocks, then when they die off, they will release all of these back into the tank. If I am wrong, then my apologies.