It seems unlikely to me that it is algae with no chlorine consumption overnight and only a slight CC reading. Ben may think differently.

Just wanted to ask about that high CH reading? Are you using cal-hypo? If so, no more. That is pretty high and along with high pH and high alk may cause you some issues at some point. Also, don't use your salt cell to keep the pool at shock level. It will shorten the cell life. Use a different chlorine source and then once you are just back in maintenance mode, turn your SWCG back on.