Just an update. Decided to give CL one last shot. As Richard and I discussed, my CYA was high so I did a drain and refill and have the CYA at 30PPM now. Also gave up on the salt since Richard suggest that it oxidize the CL faster. Things appear to be much more stable after the refill. I can hold a CL greater than 6PPM for a day day or two now so maintaining the tub with CL is now tolerable.