Hello; Two comments. First get a look at the water company report if you are on tap water. I believe they are required to publish annually. I can get a copy from my company by stopping the office. If you are lucky, as I am, and the only treatment chemical used is chlorine you can use the water storage method. However, and this is important, if they use chloramine the storage method will not work and some sort of water conditioner must be used.
Next, if you need a conditioner the powder form called SAFE is a less expensive way to use it. I got a 2.2 pound bottle of SAFE at a fish shop (where prices are not the cheapest) for $31.99. It is supposed to treat up to 200,000 gallons. I did the math once but forget, anyway it is cheap enough.
One note on the powdered SAFE. It is my understanding that a mixed batch is good for about 30 days, so do not mix up too much.
PRIME is the same chemical as the SAFE being different in that it is in liquid form. I understand they put some sort of stabilizer in the SAFE so that the bottle will have a very long shelf life. A small 100 ml bottle cost me $4.99 at the same fish store. It will treat 1000 gallons. Not as cheap to use as the SAFE.
Why do I have the stuff around if I use the water storage method? Because I sometimes need water pretty quick and I sometimes decontaminate tanks and equipment in a clorox solution. The safe/prime will help detox the clorox residue.
Good luck