No theory. We know exactly why. Your CYA level is 100ppm which is very high.. That means you need to SHOCK the pool at about 25ppm and maintain it between 8 and 15ppm.
The tabs and powders you keep using keep raising the CYA level so you can't keep the pool clear.
It can be done--you just must follow the "Best Guess" table here on the Forum and use an FAS-DPD chlorine test kit to measure it.
Or you can dump about half of the water and refill it with fresh and use only liquid chlorine. That will put the CYA around 50 which means you shock at 15-20ppm and maintain roughly at 6ppm.
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