just to summarize for the OP:
- stop trusting the pool store
- Accurately determine your stabilizer level (cyanuric acid, or CYA) by investing in a recommended testing kit
- Use the CYA/FC chart linked above to understand what your target FC level should be. If you stay above the minimum, your pool will stay sanitized and will also prevent algae growth.
- A cya of 35 or 50 or 60 doesn't change the process. Since 99% of chlorine is bound to the stabilizer, the higher FC levels don't equate to higher active chlorine levels. Just keep above the minimum at all times for whatever your CYA is. There is some small decrease in burn-off for higher CYA levels, but at 30ppm you're already like 95% of the way there.
- If you do have an algae bloom, we here don't SHOCK the pool. We raise the FC to a shock level and keep it above that level until 3 criteria are passed that let you know you've beaten the bloom.
You can swim when the FC drops below the SLAM, but at that point you are no longer outpacing algae growth and you could extend the process by a few days because of that small window where you let the FC drop. So, you'll have to decide how bad you want to swim.
You can keep the pool sanitized with low levels of active chlorine, but preventing algae growth requires a higher concentration. Weekly shocking, algaecides, phosphate removers, all those
can prevent algae growth. But the TFPC method just requires add in some liquid chlorine every day to stay above that minimum. Then you never even need the other stuff. It's easier and cheaper.
CC are the result of the chlorine acting on organics in the water. For a healthy pool, this level is 0.2 or below. The UV from the sun destroys the CC. If your CC is higher than that, then your chlorine is working on a nascent growth: an algae bloom, or maybe a bunch of kids peed in the pool
Or maybe you're all set and was just wondering about Cal-hypo....