How has your cya changed so much over the life of this thread --- 41, 30, 0, 11. (I'm not even sure how you could discern a reading of 11.)

Regardless of which number is right, a shock level of 30 is plenty high enough. Are you letting the cl level fall off during the day or sustaining it with frequent testing and frequent dosing with bleach?

I'm sure it seems as if this is never gonna end. We have had several posters this year with this same problem --- excessive chlorine demand and taking a ton of chlorine to finally rid the pool of CC and have FC hold overnight. But, it does finally get there. I hope you have been reading some of those other threads and get some hope for your pool when you read of another person's pool that has made it through. I'm sorry it is taking so long ................