Well, with a CYA that high, the water won't "look" good for very long.
Every morning when I wake up and everyday when I get home from work I have this terrible feeling that I'm going to look out and see a swamp. I don't see how the previous owner was maintaining even close to the required minimum for FC...and even if he was semi-trying to do so, it was all pucks and granular dichlor so it would have just kept getting worse. Maybe he was just shocking the **** out of it with the dichlor every few days and that was (unintentionally from his perspective) keeping it near an appropriate level.
More bizarre is the pool went unattended after we moved in and yet it was crystal clear the whole time...like a week or two after we moved, the FC measured under 1.0 and still was fine. Now a couple weeks later it's been under 10.0 for over a week now and crystal clear. Extremely fortunate I guess...