The AA treatment itself does not cloud the water. However, when the FC is zero, algae can start to grow. Usually that takes about a day before the water starts to look dull and then gets cloudier before a full-fledged algae bloom appears. So in your case, adding a metal sequestrant and then careful shocking of the water (lowering the pH first since you don't want the pH to rise too much when shocking) would have killed off the algae which would have then cleared by filtration. The clarifier might have slightly sped up that process, but if something is going to get filtered out anyway, clarifiers don't make it go any faster. Clarifiers are only helpful for dissolved compounds/particles that are too small to get caught in the filter. A cartridge or DE filter will usually catch the larger sized algae cells as well as algae clumps. Sand filters don't do as well, but the algae will often clump up and get caught in such filters as well.