Posting info from email exchange:

Test results - 7/28/2014:
FC:1.9; CC: 0.3; pH:7.6; TA:140; CH:100; CYA: 42; Salt:3; PO4:200.
Water color:blue; clarity:Clear; odor:No odor; algae:No algae; feel:soft, maybe soapy
Actions:Vacuumed pool, Added chemicals "20 oz. Knock Out Algaecide; 5 lbs. Chlor-Guard Granules"

Equipment:
21k gal 16x36 vinyl rectangle with both solar and safety covers; 3' - 8' depth; Jandy AquaPure SWCG; Jacuzzi 200 filter; Pentair 3/4 HP single speed pump running 24/7; Heat pump and fountain or waterfall.
Pool is in Pittsburgh, PA area. Using Morton pool salt from Walmart.


Pictures:

Steps:



Pool cleaner bag, after 24 hours of use.

Has tried both ascorbic acid and trichlor tabs, without noticeable effect.