You may want to sample the bottom of your pond to see what is happening down there. Is it sediment or muck and how deep? If it is muck, as your water becomes more clear, i.e. crawdad boil, you may want to put a diffuser on the bottom to create more aerobic conditions.
Since it was recently renovated, you'll have a good idea of your pond management practices the past 2 years by sampling the bottom.
