Buy Swimming Pool Chemicals from the Grocery Store!
Virtually all grocery stores have bleach (sodium hypochlorite), baking soda, and borax. Household bleach (5.25%) at $1/gallon is no great bargain -- but it's a functional substitute for any chlorine compound, and easy to get when you are in a hurry.
One gallon of bleach is equal in chlorine content to 2/3 lb. of shock (calcium hypochlorite). Put another way, one gallon will add about 2 ppm chlorine to a 30,000 gallon pool.
And baking soda, at $0.40/lb. is a whole lot cheaper than "Alkalinity Increaser" for $1.10/lb. Both are 100% sodium bicarbonate.
Borax (20 Mule Team brand) is several dollars cheaper than a patented,
branded material also containing 100% sodium tetraborate and is a good
substitute for "PH-UP" -- especially in spas -- and is at least $0.50/lb.
cheaper.
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