cartridge filter maintenence

[SeanB.]

When I used to keep a fresh water aquarium, there was a product called Filter Aid that I used from time to time that was basically a very viscous solution that could be added to the sponge filter (1 drop per gallon, I think) to coagulate small particles. It removed even the smallest particles and gave you polished water in a very short amount of time.

I wonder if there is anything similar for pool filters and what the long term effect might be. It would be a short term fix, but might be nice to get the water really pristine for a party or something.

Anyone seen anything like this for pools?

EDIT: Did a little research on my own, and it looks like I'm talking about clarifiers. I'm going to have a cartrige filter, so may have need for something like this from time to time - any one better than the others?