Did I just waste my Polyquat?

[CarlD]

Really? I've never had a problem with my method. Of course, I shock my pool till it's clean before the PQ goes in.

[chem geek]

Polyquat itself is far too small a molecule to get caught even in a DE filter or in a slime bag. However, Polyquat coagulating with particulate matter in the pool will get filtered out since Polyquat is not only an algaecide but is also a clarifier. However, this won't happen if your pool is clean.

[CarlD]

Polyquat itself is far too small a molecule to get caught even in a DE filter or in a slime bag. However, Polyquat coagulating with particulate matter in the pool will get filtered out since Polyquat is not only an algaecide but is also a clarifier. However, this won't happen if your pool is clean.

Thanks Richard. That's a GREAT explanation and it fits both Lisa's and my scenarios perfectly: If the pool is messy the PQ will tie particles up that then pull both into the filter medium. But if the pool is clean, the PQ will pass through the filter and into the water.