How much polyquat 60

[Gunnert]

Getting ready to close pool for the first time but can't find how much polyquat 60 to add to pool. My pool is 19,800 gallons.

 

[chem geek]

I would close with at maximum amount allowed on the label which is the "visible algae" amount which is 16 ounces per 10,000 gallons. Just keep in mind that it will create a chlorine demand of around 3.5 ppm FC and that such chlorine demand is independent of pool volume, assuming you are scaling up the dosing of Polyquat per the instructions. See this post for the closing instructions from Buckman Labs. So after you've added the Polyquat, you may need to bring up the FC level again to compensate (depending on how much FC you started with before adding the Polyquat).