It's impossible to tell without good test numbers. You'll need to get chlorine levels (both free--FC and combined-CC), pH, Total Alkalinity (TA), and Stabilizer/CYA. If it's a concrete or other hard material (not vinyl), you'll need Calcium Hardness (CH) as well.
The "Best Guess" table tells you what level of Free Chlorine you need, relative to your stabilizer level. But how much to add? Well there's a formula, but the shortcut is that one gallon of 6% bleach will add about 2.4 ppm of Free Chlorine to your pool. That doesn't mean it will RAISE your FC level that much, at least not for long...algae may break it down. 12% liquid chlorine (sometimes called Liquid Shock) will add double that per gallon, or 4.8ppm.
The best investment you can make is the $50 to $70 for a Taylor FAS-DPD full test kit, the K-2006 or K-2006C. It's not on my sig right now but is on Pooldoc's and on some of the other mods. The kit will pay for itself hundreds of times over and all the test chems ("reagents") are replaceable.
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