Somewhere on this website I think I saw a chart that had %FC loss versus CYA level, but I can't seem to find it. I've seen posts that say things like 90% loss in 30 minutes in noon time sun with 0 CYA, but I'd like to see the table.
Currently, I have 0 CYA. Before adding some, I wanted to get some data on FC loss at 0 CYA, at 10 ppm CYA, etc.
Also, it seems like presenting FC loss as %FC loss versus CYA ppm is misleading. You need more FC for the same sanitation level as CYA increases. So, a given percentage FC loss means more chlorine is needed to replace the loss at higher CYA than lower CYA.
An interesting chart would be FC loss in ppm versus CYA in ppm, or FC loss in ppm at the minimum FC level for sanitation versus CYA in ppm. That would show the relative amount of chlorine depletion.