I am using the TFPC method in my pool and switched to chlorine in my hot tub this year as well. Both are better than they've ever been so I am very happy with this method. I drain the hot tub in the winter and leave it empty so it has only been running with chlorine since early April. I followed Nitro's thread to start up the hot tub, using dichlor until my CYA reached target and since then the only thing I have added is a quarter cup or so of liquid chlorine after each use and hose water as needed to replace lost water. My water is clear with no odor, tests perfect and there's nothing in the filter but bits of leaves and other small debris which I clean every few days. It took me a couple of weeks to balance the water until the pH and TA were stable so I'm not in any hurry to drain it and start over unless there's some reason to. My hot tub instructions say to drain and re-fill every 90 days. Is this really necessary and if so, why? The tub is was flushed at the end of last year so it is really clean.