If the LMB that you stocked survive and thrive they will take care of the BH YOY and after a few years the BH will fade away with only a few remaining. That same comment applies to the common carp. Once those bottom dwellers quite stirring things up the water will probably clear up somewhat.

As Omaha stated you are probably not fishing for the LMB in the right areas. They will be in relatively shallower water unless the water gets very warm. They will relate to structure in those shallower areas.

What part of Iowa?

Life is Good on Bremer Pond!