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Chlorine's life expectancy in unstabilized water can be measured in minutes. The "shock" may not have any stabilizer in it. The pucks will, but not enough will be dissolved yet to do anything for you.
Three 8 ounce pucks, when they're fully dissolved, will only add about 10 CYA to your pool. That's not even high enough to register on a test.
So... thus far, you haven't done anything necessarily wrong, you're just not attacking things the right way. First thing you need to do is find the empty "shock" bags and find out what was inside. There are three common chemicals all marketed as "shock." A basic rule: never add anything to the pool unless you know what it is.
To do things right, you need some test results so you can add what the pool needs and only what the pool needs. The pool store testing won't cut it. Neither will test strips. That's a pretty big pool you have there, it requires a grown-up test kit.
Pool School - Test Kits Compared Without test resuts, there isn't a whole lot we can tell you. Order a good one. Don't try to save a few bucks. It's an investment.
Then move on over to Pool School. Start with
Pool School - ABCs of Pool Water Chemistry
A few hours study, a test kit, and some learning-by-doing combined with this forum will get your pool shaped up quickly.