I can't explain why the higher CYA works better for me, but it does. If I kept my CYA at 50, I'd be pouring stuff in the pool constantly, trying to keep it clean. The best I can suggest is that you up the CYa by 10 ppm, and see if that does anything to lower your chlorine loss. If so, then up it a little at a time until you get to the lowest level of CYA that will keep the chlorine in the pool.

The trace of CC you're seeing is probably just pollen or other airborne "stuff" that the chlorine is burning off--once the sun hits the pool, it will take care of the CC if it stays that low. Sweat, suncscreen, etc can contribute to it, too. That's why we wait until CC gets to 1 or higher before we recommend shocking the pool. As long as it's not staying above 0.5, and you are not losing chlorine overnight, then your usual chlorination will take care of it.

Janet