No problem at all, I realize my "problem" really isn't one at this point. I've ordered a new K2006 test kit, once that arrives I may well find out that all my readings were bogus due to expired reagents.

To update my water situation, you were right about the impending algae. A couple of days ago I checked chlorine level in the morning before the SWCG was running and found it at zero. Brought it up to about 10 with cal hypo shock and kept it there for 24 hours, after which it was crystal clear and has stayed that way for 48 hours with no other chemical additions. Chlorine level holding overnight, so it looks like the problem is solved. Thank you for pointing me in the right direction.