I'm in the shock process due to recent downpours (with low FC in a SWG pool).

Q1 When you start the shock process should you add all the chlorine you can even if it doesn't get you to the shock level?
i.e. if you need 6 gal but only have a couple of gallons available until the next day. Is any chlorine good to add or will it just be wasted until you can fully shock?

Q2 During shocking, is there a good reason to run a 2 speed pump on high, or is any circulation adequate?
Is shocking a chemical process that just takes "X" amount of time or does circulation and filtration play a large part too?
(in my case, 17,500 gal with 1 1/2 hp pump and sand filter).

Thanks, John

Hi, John,

1. While it is not an ABSOLUTE requirement, it is much better to bring your FC up to the prescribed level all at once. If you don't have enough, save it until you have an adequate amount on hand......not only for the initial dose but your follow up doses as well.


2. Think of the FC as providing the "kill" and filtration and circulation to get rid of the "bodies". In that respect, there is some advantage to circ and filter as powerfully as possible to clear the water as quickly as you can. What's equally or perhaps more important is to keep your filter clean so it won't get jammed up with the "bodies"

Dave that is a great analogy.

X 2

Wait until you have enough. What you add will just get used up and the algae will start reproducing again before the rest of the chlorine gets added. So the first dose was wasted.

Shocking means killing the algae faster than it can reproduce.

That makes good sense.
Thank you all for the replies.
John