2 possibilities:

1. The polyquat has clumped stuff together, so it's easier to filter -- but also easier to see.

Solution? Run the pump & filter 24/7.


2. You had some mystery pool-store goop in the water that you hadn't mentioned, but that was anionic in solution (negatively charged on the big portion of the ionic pair). Polyquat is cationic and isn't compatible with anionic products. Some 'flocculants' fall into this category.

Solution? Run the pump & filter 24/7 . . . but it will take longer.