When your solids are not settling, this is due to filaments and dead bacteria. Your best option is to use our VitaStim Low F:M. Designed for low food to microorganism conditions, VitaStim Low F:M will allow for a robust biomass of flock-forming bacteria to form and prevent filamentous bulking and cloudy effluent by introducing biostimulants and micronutrients. Aquafix often prescribes this as a buffer for many situations including septicity, restarting tank/plant, and poor settling. For best result combine with Foam Buster.
The diagram below will give you an idea on better understanding your settling and point you in the right direction of a obtaining a clear effluent.