I would shock the pool. At the CYA level of 30 ppm you reported, I would shock to at least 12 ppm FC (Ben's chart says 15 ppm so you can do that instead -- 30 ppm CYA is at the low end of the range) and hold it there until the following three things occur: 1) water is crystal clear (it may already be), 2) FC does not drop overnight or does so minimally (0.5 ppm is on the edge), 3) you do not measure any significant CCs (< 0.5 ppm). So your measurement overnight is on the edge so shocking would be reasonable to do.