Sorry Watermom... Somehow I missed your last post until now. Thanks for the reply! Yes it is a vinyl lined pool. When you say Best Guess Chlorine Chart.. that does include the far right column... correct? If I read things correctly about brown/ mustard algae, you need to shock at above normal shock levels, or did I miss something??

Thanks for all the help and patience! So much information to take in.. but well worth it!