1.3 gallons would only take your pool to 2.8 ppm per the bleach calculator so that would definitely not be enough for a pool this big. 2.7 would take it to 5.9. What size are the bottles of bleach you are adding? Remember, the small jugs they sell aren't gallons - they are 3 quarts. The large jugs are something like 174 oz. (if I am remembering right) which would be approximately 1.25 gallons.
How does your pool look? You may want to consider shocking your pool on the chance that you are fighting something in there and that is the reason for the higher than expected chlorine consumption. My other idea is that perhaps your cya is closer to 35 than 45 and that you may need to bump it up just a little.
Or, you may just want to take your chlorine a little higher each evening - maybe to 8 and see if that will last you through til the next evening.
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