PolyQuat has the least side effects of all algaecides so it's not a disaster that you used it. Mostly, if you add large amounts it will consume chlorine so you'll need to add more chlorine. With PolyQuat, it's mostly that it was not necessary than being a real problem.

PolyQuat is much better at helping to prevent algae, such as when the chlorine gets too low for a brief time, than it is killing an existing algae bloom. It simply kills too quickly to keep up with a full bloom. Shocking with chlorine is the best way to get rid of algae, even if it's a LOT of algae as shown in this thread.

Richard