What chemicals are needed for closing?

First, thanks for prior advice. After my pool guy charged about $200 for chemicals to open, I learned from this forum, and bought my own chemicals for well under $100 this year.
My pool is a little over 20,000 gallons, with a salt chlorinator, concrete gunite. What chemicals should I get for closing, and where is the best place to purchase them? Should I shock the pool with my chlorinator?

It all depends on what your current chem values are - could you please post the

FC
CC or TC
ALK
CALCIUM HARDNESS
CYA

You'll want to shock the pool (how much bleach you need depends on the CYA and % of the bleach) A lot of people add polyquat 60% for the winter - the bleach and the poly wipe each other out so shock first and hold it for a day or 2 then add the poly. (polyquat isn't required, but is a nice insurance policy against algae over the winter)

What kind of cover do you use?

$200 for opening chems is outrageous!!:eek: Unless your numbers are way out of whack and you're fighting algae ~$30 should do it:)

Please let us know your numbers and we'll be able to tell you what and how much of each to add.

While Waste is correct, mostly you need enough chlorine to shock your pool.

If you have lines than can collect water even after you drain them, you'll need pool line antifreeze.

You may need to balance your pH with Borax and Muriatic Acid.

I like to add a quart of PolyQuat 60% just before closing.

But, unless you have a problem to solve, that's it.

Me? It's usually just chlorine (IE bleach) and PolyQuat.